Questions 29 to 31 are based on the passage you have just heard。
29. What have people all over the world begun to recognize?
30. Who has been liberated from long hours of hard work?
31. When was the value of work a major concept in American life?
Passage Three
Until recently, a tomato was just a tomato. But now scientists have begun to change the genes of plants in laboratories, so it is not as easy to know when tomatoes are pure tomatoes. That is true with many other vegetables and fruits。
Genetic engineering is the process of taking genes from one plant or animal and putting them into another plant or animal. Scientists use the process to increase the nutrients a food contains. However, this new genetic engineering technology has raised a lot of questions。
The United States Food and Drug Administration is responsible for deciding how foods must be described when they are sold. The FDA says people who buy human foods produced by new kinds of plants must be told if there are any safety problems. It also says people must be told what nutrients the foods contain。
There are, however, times when more information about a new food product would be helpful. Some foods are not a safety threat, but do affect people in unusual ways. After eating the food, they may develop red spots on their skin, or have trouble breathing or have a sick stomach。
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