Many jobs must be done with two people. One person takes the lead. The other helps. So it is with the human body. Much of our body depends on the cooperation between substances. When they work together, chemical reactions take place smoothly. Body systems are kept in balance. Some of the most important helpers in the job of good health are the substances we call vitamins. The word "vitamin" dates back to Polish scientist Casimir Funk in 1912. He was studying a substance in rice. Funk believed the substance belonged to a group of chemicals known as amines  . He added the Latin word "vita", meaning life. So he called the substance a "vitamine"--an amine necessary for life. Other studies found that not all vitamins were amines. So the name was shortened to vitamin. But Funk was correct in recognizing their importance. Scientists have discovered 14 kinds of vitamins. They say vitamins help to carry out chemicals changes within cells. If we do not get enough of the vitamins, we are at risk of developing a number of diseases. _ brings us back to James Lind of Scotland. In the 1740s, Lind was a doctor for the British Navy. He was investigating a problem that had existed in the Navy for many years. The problem was the disease scurvy . The sailors were weak from bleeding inside their bodies. Even the smallest wound would not heal. Doctor Lind thought the sailors were getting sick because they failed to eat some kinds of foods when they were at sea for many months. Doctor Lind separated twelve sailors who had scurvy into two groups. He gave each group different foods to eat. One group got oranges and lemons. The other did not. The men who ate the fruit began to improve within seven days. The other men got weaker. However, which foods should be eaten to keep us healthy? Let us look at some important vitamins for these answers. What is the main topic of the passage?
Food to keep us healthy. The benefits of vitamins. Research into scurvy. Facts about vitamins.
Question: Many jobs must be done with two people. One person takes the lead. The other helps. So it is with the human body. Much of our body depends on the cooperation between substances. When they work together, chemical reactions take place smoothly. Body systems are kept in balance. Some of the most important helpers in the job of good health are the substances we call vitamins. The word "vitamin" dates back to Polish scientist Casimir Funk in 1912. He was studying a substance in rice. Funk believed the substance belonged to a group of chemicals known as amines  . He added the Latin word "vita", meaning life. So he called the substance a "vitamine"--an amine necessary for life. Other studies found that not all vitamins were amines. So the name was shortened to vitamin. But Funk was correct in recognizing their importance. Scientists have discovered 14 kinds of vitamins. They say vitamins help to carry out chemicals changes within cells. If we do not get enough of the vitamins, we are at risk of developing a number of diseases. _ brings us back to James Lind of Scotland. In the 1740s, Lind was a doctor for the British Navy. He was investigating a problem that had existed in the Navy for many years. The problem was the disease scurvy . The sailors were weak from bleeding inside their bodies. Even the smallest wound would not heal. Doctor Lind thought the sailors were getting sick because they failed to eat some kinds of foods when they were at sea for many months. Doctor Lind separated twelve sailors who had scurvy into two groups. He gave each group different foods to eat. One group got oranges and lemons. The other did not. The men who ate the fruit began to improve within seven days. The other men got weaker. However, which foods should be eaten to keep us healthy? Let us look at some important vitamins for these answers. What is the main topic of the passage?
A. Food to keep us healthy.
B. The benefits of vitamins.
C. Research into scurvy.
D. Facts about vitamins.
Answer: