Martin Luther King, Jr., is renowned for his contributions to the civil rights movement and his notable orations, including the impactful "I Have A Dream" speech. But fewer people know much about King's childhood. M.L., as he was called, was born in 1929 in Atlanta, Georgia, at  the home of his maternal grandfather. M.L.'s grandfather, the Reverend A.D. Williams, purchased their home on Auburn Avenue in 1909, twenty years before M.L. was born. The Reverend Williams, an eloquent speaker, played an important role in the community since so many people's lives centered around the church. He allowed his church and his home  to be used as a meeting place for a number of organizations dedicated to the education and social advancement of blacks. M.L. grew up in this atmosphere, with his home being used as a community gathering place, and was no doubt influenced by it.

 M.L.'s childhood was not especially eventful. His father was a minister and his mother was a musician. He was the second of three children, and he attended all- black schools in a black neighborhood. The neighborhood was not poor, however. Auburn Avenue was the main artery through a prosperous neighborhood that had come to symbolize achievement  for Atlanta's black people. It was an area of banks, insurance companies, builders, jewelers, tailors, doctors, lawyers, and other black-owner black-operated businesses and services. Even in the face of Atlanta's segregation, the district thrived. Dr. King never forgot the community spirit he had known as a child, nor did he forget the racial prejudice  that was a seemingly insurmountable barrier that kept black Atlantans from mingling with whites.

1. What is this passage mainly about?

Martin Luther King, Jr., is renowned for his contributions to the civil rights movement and his notable orations, including the impactful "I Have A Dream" speech. But fewer people know much about King's childhood. M.L., as he was called, was born in 1929 in Atlanta, Georgia, at  the home of his maternal grandfather. M.L.'s grandfather, the Reverend A.D. Williams, purchased their home on Auburn Avenue in 1909, twenty years before M.L. was born. The Reverend Williams, an eloquent speaker, played an important role in the community since so many people's lives centered around the church. He allowed his church and his home  to be used as a meeting place for a number of organizations dedicated to the education and social advancement of blacks. M.L. grew up in this atmosphere, with his home being used as a community gathering place, and was no doubt influenced by it.

M.L.'s childhood was not especially eventful. His father was a minister and his mother was a musician. He was the second of three children, and he attended all- black schools in a black neighborhood. The neighborhood was not poor, however. Auburn Avenue was the main artery through a prosperous neighborhood that had come to symbolize achievement  for Atlanta's black people. It was an area of banks, insurance companies, builders, jewelers, tailors, doctors, lawyers, and other black-owner black-operated businesses and services. Even in the face of Atlanta's segregation, the district thrived. Dr. King never forgot the community spirit he had known as a child, nor did he forget the racial prejudice  that was a seemingly insurmountable barrier that kept black Atlantans from mingling with whites.

2. The word "eloquent" means most nearly

Martin Luther King, Jr., is renowned for his contributions to the civil rights movement and his notable orations, including the impactful "I Have A Dream" speech. But fewer people know much about King's childhood. M.L., as he was called, was born in 1929 in Atlanta, Georgia, at  the home of his maternal grandfather. M.L.'s grandfather, the Reverend A.D. Williams, purchased their home on Auburn Avenue in 1909, twenty years before M.L. was born. The Reverend Williams, an eloquent speaker, played an important role in the community since so many people's lives centered around the church. He allowed his church and his home to be used as a meeting place for a number of organizations dedicated to the education and social advancement of blacks. M.L. grew up in this atmosphere, with his home being used as a community gathering place, and was no doubt influenced by it.

 M.L.'s childhood was not especially eventful. His father was a minister and his mother was a musician. He was the second of three children, and he attended all- black schools in a black neighborhood. The neighborhood was not poor, however. Auburn Avenue was the main artery through a prosperous neighborhood that had come to symbolize achievement  for Atlanta's black people. It was an area of banks, insurance companies, builders, jewelers, tailors, doctors, lawyers, and other black-owner black-operated businesses and services. Even in the face of Atlanta's segregation, the district thrived. Dr. King never forgot the community spirit he had known as a child, nor did he forget the racial prejudice  that was a seemingly insurmountable barrier that kept black Atlantans from mingling with whites.

The word "gathering"  could best be replaced by

Martin Luther King, Jr., is renowned for his contributions to the civil rights movement and his notable orations, including the impactful "I Have A Dream" speech. But fewer people know much about King's childhood. M.L., as he was called, was born in 1929 in Atlanta, Georgia, at  the home of his maternal grandfather. M.L.'s grandfather, the Reverend A.D. Williams, purchased their home on Auburn Avenue in 1909, twenty years before M.L. was born. The Reverend Williams, an eloquent speaker, played an important role in the community since so many people's lives centered around the church. He allowed his church and his home to be used as a meeting place for a number of organizations dedicated to the education and social advancement of blacks. M.L. grew up in this atmosphere, with his home being used as a community gathering place, and was no doubt influenced by it.

 M.L.'s childhood was not especially eventful. His father was a minister and his mother was a musician. He was the second of three children, and he attended all- black schools in a black neighborhood. The neighborhood was not poor, however. Auburn Avenue was the main artery through a prosperous neighborhood that had come to symbolize achievement  for Atlanta's black people. It was an area of banks, insurance companies, builders, jewelers, tailors, doctors, lawyers, and other black-owner black-operated businesses and services. Even in the face of Atlanta's segregation, the district thrived. Dr. King never forgot the community spirit he had known as a child, nor did he forget the racial prejudice  that was a seemingly insurmountable barrier that kept black Atlantans from mingling with whites.

According to the author, blacks in King's neighborhood were involved in all the following businesses and services EXCEPT

Martin Luther King, Jr., is renowned for his contributions to the civil rights movement and his notable orations, including the impactful "I Have A Dream" speech. But fewer people know much about King's childhood. M.L., as he was called, was born in 1929 in Atlanta, Georgia, at  the home of his maternal grandfather. M.L.'s grandfather, the Reverend A.D. Williams, purchased their home on Auburn Avenue in 1909, twenty years before M.L. was born. The Reverend Williams, an eloquent speaker, played an important role in the community since so many people's lives centered around the church. He allowed his church and his home to be used as a meeting place for a number of organizations dedicated to the education and social advancement of blacks. M.L. grew up in this atmosphere, with his home being used as a community gathering place, and was no doubt influenced by it.

 M.L.'s childhood was not especially eventful. His father was a minister and his mother was a musician. He was the second of three children, and he attended all- black schools in a black neighborhood. The neighborhood was not poor, however. Auburn Avenue was the main artery through a prosperous neighborhood that had come to symbolize achievement  for Atlanta's black people. It was an area of banks, insurance companies, builders, jewelers, tailors, doctors, lawyers, and other black-owner black-operated businesses and services. Even in the face of Atlanta's segregation, the district thrived. Dr. King never forgot the community spirit he had known as a child, nor did he forget the racial prejudice  that was a seemingly insurmountable barrier that kept black Atlantans from mingling with whites.

According to the author, King was influenced by

Martin Luther King, Jr., is renowned for his contributions to the civil rights movement and his notable orations, including the impactful "I Have A Dream" speech. But fewer people know much about King's childhood. M.L., as he was called, was born in 1929 in Atlanta, Georgia, at  the home of his maternal grandfather. M.L.'s grandfather, the Reverend A.D. Williams, purchased their home on Auburn Avenue in 1909, twenty years before M.L. was born. The Reverend Williams, an eloquent speaker, played an important role in the community since so many people's lives centered around the church. He allowed his church and his home to be used as a meeting place for a number of organizations dedicated to the education and social advancement of blacks. M.L. grew up in this atmosphere, with his home being used as a community gathering place, and was no doubt influenced by it.

 M.L.'s childhood was not especially eventful. His father was a minister and his mother was a musician. He was the second of three children, and he attended all- black schools in a black neighborhood. The neighborhood was not poor, however. Auburn Avenue was the main artery through a prosperous neighborhood that had come to symbolize achievement  for Atlanta's black people. It was an area of banks, insurance companies, builders, jewelers, tailors, doctors, lawyers, and other black-owner black-operated businesses and services. Even in the face of Atlanta's segregation, the district thrived. Dr. King never forgot the community spirit he had known as a child, nor did he forget the racial prejudice  that was a seemingly insurmountable barrier that kept black Atlantans from mingling with whites.

According to the author, M.L.

Carbohydrates, encompassing saccharides, constitute an indispensable component of a nutritious dietary regimen. They serve as the primary reservoir of energy for the human organism, and they also function to flavor and sweeten foods. Carbohydrates range from simple sugars like glucose to complex sugars such as amylose and  amylopectin. Nutritionists estimate that carbohydrates should make up about one-fourth to one-fifth of a person's diet. This translates to about 75-100 grams of carbohydrates per day. 

A diet that is deficient in carbohydrates can have an adverse effect on a person's health. When the body lacks a sufficient amount of carbohydrates it must then use its protein supplies for energy, a process called gluconeogenesis. This, however, results in a lack of necessary protein, and further health difficulties may occur.

A lack of carbohydrates can also lead to ketosis, a build-up of ketones in the body that causes fatigue, lethargy, and bad breath.

What is the main idea of this passage?

Carbohydrates, encompassing saccharides, constitute an indispensable component of a nutritious dietary regimen. They serve as the primary reservoir of energy for the human organism, and they also function to flavor and sweeten foods. Carbohydrates range from simple sugars like glucose to complex sugars such as amylose and  amylopectin. Nutritionists estimate that carbohydrates should make up about one-fourth to one-fifth of a person's diet. This translates to about 75-100 grams of carbohydrates per day. 

A diet that is deficient in carbohydrates can have an adverse effect on a person's health. When the body lacks a sufficient amount of carbohydrates it must then use its protein supplies for energy, a process called gluconeogenesis. This, however, results in a lack of necessary protein, and further health difficulties may occur.

A lack of carbohydrates can also lead to ketosis, a build-up of ketones in the body that causes fatigue, lethargy, and bad breath.

5. According to the passage, what do most nutritionists suggest?

Carbohydrates, encompassing saccharides, constitute an indispensable component of a nutritious dietary regimen. They serve as the primary reservoir of energy for the human organism, and they also function to flavor and sweeten foods. Carbohydrates range from simple sugars like glucose to complex sugars such as amylose and  amylopectin. Nutritionists estimate that carbohydrates should make up about one-fourth to one-fifth of a person's diet. This translates to about 75-100 grams of carbohydrates per day. 

A diet that is deficient in carbohydrates can have an adverse effect on a person's health. When the body lacks a sufficient amount of carbohydrates it must then use its protein supplies for energy, a process called gluconeogenesis. This, however, results in a lack of necessary protein, and further health difficulties may occur.

A lack of carbohydrates can also lead to ketosis, a build-up of ketones in the body that causes fatigue, lethargy, and bad breath.

Which of the following do carbohydrates NOT do?

Carbohydrates, encompassing saccharides, constitute an indispensable component of a nutritious dietary regimen. They serve as the primary reservoir of energy for the human organism, and they also function to flavor and sweeten foods. Carbohydrates range from simple sugars like glucose to complex sugars such as amylose and  amylopectin. Nutritionists estimate that carbohydrates should make up about one-fourth to one-fifth of a person's diet. This translates to about 75-100 grams of carbohydrates per day. 

A diet that is deficient in carbohydrates can have an adverse effect on a person's health. When the body lacks a sufficient amount of carbohydrates it must then use its protein supplies for energy, a process called gluconeogenesis. This, however, results in a lack of necessary protein, and further health difficulties may occur.

A lack of carbohydrates can also lead to ketosis, a build-up of ketones in the body that causes fatigue, lethargy, and bad breath.

10. The word "lacks"  is most similar to which of the following?

Carbohydrates, encompassing saccharides, constitute an indispensable component of a nutritious dietary regimen. They serve as the primary reservoir of energy for the human organism, and they also function to flavor and sweeten foods. Carbohydrates range from simple sugars like glucose to complex sugars such as amylose and  amylopectin. Nutritionists estimate that carbohydrates should make up about one-fourth to one-fifth of a person's diet. This translates to about 75-100 grams of carbohydrates per day. 

A diet that is deficient in carbohydrates can have an adverse effect on a person's health. When the body lacks a sufficient amount of carbohydrates it must then use its protein supplies for energy, a process called gluconeogenesis. This, however, results in a lack of necessary protein, and further health difficulties may occur.

A lack of carbohydrates can also lead to ketosis, a build-up of ketones in the body that causes fatigue, lethargy, and bad breath.

Which of the following best describes the author's tone?

Carbohydrates, encompassing saccharides, constitute an indispensable component of a nutritious dietary regimen. They serve as the primary reservoir of energy for the human organism, and they also function to flavor and sweeten foods. Carbohydrates range from simple sugars like glucose to complex sugars such as amylose and  amylopectin. Nutritionists estimate that carbohydrates should make up about one-fourth to one-fifth of a person's diet. This translates to about 75-100 grams of carbohydrates per day. 

A diet that is deficient in carbohydrates can have an adverse effect on a person's health. When the body lacks a sufficient amount of carbohydrates it must then use its protein supplies for energy, a process called gluconeogenesis. This, however, results in a lack of necessary protein, and further health difficulties may occur.

A lack of carbohydrates can also lead to ketosis, a build-up of ketones in the body that causes fatigue, lethargy, and bad breath.

Which of the following best describes the organization of this passage?

Following a span of twenty years characterized by burgeoning student admissions and economic affluence, American business schools have begun encountering harder challenges. Solely Harvard's School of Business Administration has exhibited a significant increase in enrollment during the recent years.

Both Princeton and Stanford have seen decreases in their enrollments. Since 1990, the number of people receiving Masters in Business Administration (MBA) degrees, has dropped about 3 percent to 75,000, and the trend of lower enrollment rates is expected to continue.

There are two factors causing this decrease in students seeking an MBA degree. The first one is that many graduates of four-year colleges are finding that an MBA degree does not guarantee a plush job on Wall Street, or in other financial districts of major American cities.

Many of the entry-level management jobs are going to students graduating with Master of Arts degrees in English and the humanities as well as those holding MBA degrees. Students have asked the question, "Is an MBA degree really what I need to be best prepared for getting a good job?" The second major factor has been the cutting of American payrolls and the lower number of entry-level jobs being offered. Business needs are changing, and MBA schools are struggling to meet the new demands.

1. What is the main focus of this passage?

Following a span of twenty years characterized by burgeoning student admissions and economic affluence, American business schools have begun encountering harder challenges. Solely Harvard's School of Business Administration has exhibited a significant increase in enrollment during the recent years.

Both Princeton and Stanford have seen decreases in their enrollments. Since 1990, the number of people receiving Masters in Business Administration (MBA) degrees, has dropped about 3 percent to 75,000, and the trend of lower enrollment rates is expected to continue.

There are two factors causing this decrease in students seeking an MBA degree. The first one is that many graduates of four-year colleges are finding that an MBA degree does not guarantee a plush job on Wall Street, or in other financial districts of major American cities.

Many of the entry-level management jobs are going to students graduating with Master of Arts degrees in English and the humanities as well as those holding MBA degrees. Students have asked the question, "Is an MBA degree really what I need to be best prepared for getting a good job?" The second major factor has been the cutting of American payrolls and the lower number of entry-level jobs being offered. Business needs are changing, and MBA schools are struggling to meet the new demands.

Which of the following business schools has NOT shown a decrease in enrollment?

Following a span of twenty years characterized by burgeoning student admissions and economic affluence, American business schools have begun encountering harder challenges. Solely Harvard's School of Business Administration has exhibited a significant increase in enrollment during the recent years.

Both Princeton and Stanford have seen decreases in their enrollments. Since 1990, the number of people receiving Masters in Business Administration (MBA) degrees, has dropped about 3 percent to 75,000, and the trend of lower enrollment rates is expected to continue.

There are two factors causing this decrease in students seeking an MBA degree. The first one is that many graduates of four-year colleges are finding that an MBA degree does not guarantee a plush job on Wall Street, or in other financial districts of major American cities.

Many of the entry-level management jobs are going to students graduating with Master of Arts degrees in English and the humanities as well as those holding MBA degrees. Students have asked the question, "Is an MBA degree really what I need to be best prepared for getting a good job?" The second major factor has been the cutting of American payrolls and the lower number of entry-level jobs being offered. Business needs are changing, and MBA schools are struggling to meet the new demands.

The word "seeking" could best be replaced by which of the following?

Following a span of twenty years characterized by burgeoning student admissions and economic affluence, American business schools have begun encountering harder challenges. Solely Harvard's School of Business Administration has exhibited a significant increase in enrollment during the recent years.

Both Princeton and Stanford have seen decreases in their enrollments. Since 1990, the number of people receiving Masters in Business Administration (MBA) degrees, has dropped about 3 percent to 75,000, and the trend of lower enrollment rates is expected to continue.

There are two factors causing this decrease in students seeking an MBA degree. The first one is that many graduates of four-year colleges are finding that an MBA degree does not guarantee a plush job on Wall Street, or in other financial districts of major American cities.

Many of the entry-level management jobs are going to students graduating with Master of Arts degrees in English and the humanities as well as those holding MBA degrees. Students have asked the question, "Is an MBA degree really what I need to be best prepared for getting a good job?" The second major factor has been the cutting of American payrolls and the lower number of entry-level jobs being offered. Business needs are changing, and MBA schools are struggling to meet the new demands.

Which of the following descriptions most likely applies to Wall Street?

Following a span of twenty years characterized by burgeoning student admissions and economic affluence, American business schools have begun encountering harder challenges. Solely Harvard's School of Business Administration has exhibited a significant increase in enrollment during the recent years.

Both Princeton and Stanford have seen decreases in their enrollments. Since 1990, the number of people receiving Masters in Business Administration (MBA) degrees, has dropped about 3 percent to 75,000, and the trend of lower enrollment rates is expected to continue.

There are two factors causing this decrease in students seeking an MBA degree. The first one is that many graduates of four-year colleges are finding that an MBA degree does not guarantee a plush job on Wall Street, or in other financial districts of major American cities.

Many of the entry-level management jobs are going to students graduating with Master of Arts degrees in English and the humanities as well as those holding MBA degrees. Students have asked the question, "Is an MBA degree really what I need to be best prepared for getting a good job?" The second major factor has been the cutting of American payrolls and the lower number of entry-level jobs being offered. Business needs are changing, and MBA schools are struggling to meet the new demands.

According to the passage, what are two causes of declining business school enrollments?

Following a span of twenty years characterized by burgeoning student admissions and economic affluence, American business schools have begun encountering harder challenges. Solely Harvard's School of Business Administration has exhibited a significant increase in enrollment during the recent years.

Both Princeton and Stanford have seen decreases in their enrollments. Since 1990, the number of people receiving Masters in Business Administration (MBA) degrees, has dropped about 3 percent to 75,000, and the trend of lower enrollment rates is expected to continue.

There are two factors causing this decrease in students seeking an MBA degree. The first one is that many graduates of four-year colleges are finding that an MBA degree does not guarantee a plush job on Wall Street, or in other financial districts of major American cities.

Many of the entry-level management jobs are going to students graduating with Master of Arts degrees in English and the humanities as well as those holding MBA degrees. Students have asked the question, "Is an MBA degree really what I need to be best prepared for getting a good job?" The second major factor has been the cutting of American payrolls and the lower number of entry-level jobs being offered. Business needs are changing, and MBA schools are struggling to meet the new demands.

Which of the following might be the topic of the paragraph?

A pilot cannot fly a plane by sight alone. In many conditions, such as flying at night and landing in dense fog, a pilot must use radar, an alternative way of navigating. Since human eyes are not very good at determining speeds of approaching objects, radar can show a pilot how fast nearby planes are moving. 

The basic principle of radar is exemplified by what happens when one shouts in a cave. The echo of the sounds against the walls helps a person determine the size of the cave. With radar, however, the waves are radio waves instead of sound waves. Radio waves travel at the speed of light, about 300,000 kilometers in one second. A radar set sends out a short burst of radiation waves. Then it receives the echoes produced when the waves bounce off objects. By determining the time it takes for the echoes to return to the radar set, a trained technician can determine the distance between the radar set and other objects. The word "radar," in fact, gets its name from the term "radio detection and ranging." "Ranging" is the term for detection of the distance between an object and the radar set. Besides being of critical importance to pilots, radar is essential for air traffic control, tracking ships at sea, and for tracking weather systems and storms.

1. What is the main topic of this passage?

 A pilot cannot fly a plane by sight alone. In many conditions, such as flying at night and landing in dense fog, a pilot must use radar, an alternative way of navigating. Since human eyes are not very good at determining speeds of approaching objects, radar can show a pilot how fast nearby planes are moving. 

The basic principle of radar is exemplified by what happens when one shouts in a cave. The echo of the sounds against the walls helps a person determine the size of the cave. With radar, however, the waves are radio waves instead of sound waves. Radio waves travel at the speed of light, about 300,000 kilometers in one second. A radar set sends out a short burst of radiation waves. Then it receives the echoes produced when the waves bounce off objects. By determining the time it takes for the echoes to return to the radar set, a trained technician can determine the distance between the radar set and other objects. The word "radar," in fact, gets its name from the term "radio detection and ranging." "Ranging" is the term for detection of the distance between an object and the radar set. Besides being of critical importance to pilots, radar is essential for air traffic control, tracking ships at sea, and for tracking weather systems and storms.

According to the passage, what can radar detect besides location of objects?

   A pilot cannot fly a plane by sight alone. In many conditions, such as flying at night and landing in dense fog, a pilot must use radar, an alternative way of navigating. Since human eyes are not very good at determining speeds of approaching objects, radar can show a pilot how fast nearby planes are moving. 

The basic principle of radar is exemplified by what happens when one shouts in a cave. The echo of the sounds against the walls helps a person determine the size of the cave. With radar, however, the waves are radio waves instead of sound waves. Radio waves travel at the speed of light, about 300,000 kilometers in one second. A radar set sends out a short burst of radiation waves. Then it receives the echoes produced when the waves bounce off objects. By determining the time it takes for the echoes to return to the radar set, a trained technician can determine the distance between the radar set and other objects. The word "radar," in fact, gets its name from the term "radio detection and ranging." "Ranging" is the term for detection of the distance between an object and the radar set. Besides being of critical importance to pilots, radar is essential for air traffic control, tracking ships at sea, and for tracking weather systems and storms.

Which of the following words best describes the tone of this passage?

   A pilot cannot fly a plane by sight alone. In many conditions, such as flying at night and landing in dense fog, a pilot must use radar, an alternative way of navigating. Since human eyes are not very good at determining speeds of approaching objects, radar can show a pilot how fast nearby planes are moving. 

The basic principle of radar is exemplified by what happens when one shouts in a cave. The echo of the sounds against the walls helps a person determine the size of the cave. With radar, however, the waves are radio waves instead of sound waves. Radio waves travel at the speed of light, about 300,000 kilometers in one second. A radar set sends out a short burst of radiation waves. Then it receives the echoes produced when the waves bounce off objects. By determining the time it takes for the echoes to return to the radar set, a trained technician can determine the distance between the radar set and other objects. The word "radar," in fact, gets its name from the term "radio detection and ranging." "Ranging" is the term for detection of the distance between an object and the radar set. Besides being of critical importance to pilots, radar is essential for air traffic control, tracking ships at sea, and for tracking weather systems and storms.

Which type of waves does radar use?

   A pilot cannot fly a plane by sight alone. In many conditions, such as flying at night and landing in dense fog, a pilot must use radar, an alternative way of navigating. Since human eyes are not very good at determining speeds of approaching objects, radar can show a pilot how fast nearby planes are moving. 

The basic principle of radar is exemplified by what happens when one shouts in a cave. The echo of the sounds against the walls helps a person determine the size of the cave. With radar, however, the waves are radio waves instead of sound waves. Radio waves travel at the speed of light, about 300,000 kilometers in one second. A radar set sends out a short burst of radiation waves. Then it receives the echoes produced when the waves bounce off objects. By determining the time it takes for the echoes to return to the radar set, a trained technician can determine the distance between the radar set and other objects. The word "radar," in fact, gets its name from the term "radio detection and ranging." "Ranging" is the term for detection of the distance between an object and the radar set. Besides being of critical importance to pilots, radar is essential for air traffic control, tracking ships at sea, and for tracking weather systems and storms.

Which of the following would most likely be the topic of the next paragraph?

   A pilot cannot fly a plane by sight alone. In many conditions, such as flying at night and landing in dense fog, a pilot must use radar, an alternative way of navigating. Since human eyes are not very good at determining speeds of approaching objects, radar can show a pilot how fast nearby planes are moving. 

The basic principle of radar is exemplified by what happens when one shouts in a cave. The echo of the sounds against the walls helps a person determine the size of the cave. With radar, however, the waves are radio waves instead of sound waves. Radio waves travel at the speed of light, about 300,000 kilometers in one second. A radar set sends out a short burst of radiation waves. Then it receives the echoes produced when the waves bounce off objects. By determining the time it takes for the echoes to return to the radar set, a trained technician can determine the distance between the radar set and other objects. The word "radar," in fact, gets its name from the term "radio detection and ranging." "Ranging" is the term for detection of the distance between an object and the radar set. Besides being of critical importance to pilots, radar is essential for air traffic control, tracking ships at sea, and for tracking weather systems and storms.

What might be inferred about radar?

The cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been "primed" by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed. 

Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.

 
In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective. Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.

1. What does this passage mainly discuss?

The cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been "primed" by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed. 

Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.

 
In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective. Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.

We can infer from the passage that one benefit of fluoride to healthy teeth is

The cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been "primed" by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed. 

Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.

 
In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective. Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.

What can be concluded from the passage about sweets?

The cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been "primed" by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed. 

Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.

 
In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective. Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.

It can be inferred from the passage that foods with fiber are

The cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been "primed" by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed. 

Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.

 
In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective. Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.

According to the passage, the value of eating foods with fiber is that

The cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been "primed" by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed. 

Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.

 
In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective. Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.

The author of the passage states that the amount of acid produced by the bacteria in your saliva increases