Reading Comprehension(阅读理解)Passage 2Increasingly, people have become aware of the need to change their eating habits, because much of the food they eat, particularly processed food, is not good for the health. Consequently, there has been a growing interest in natural foods: foods which do not contain chemical additives（添加剂）and which have not been affected by chemical fertilizers. Natural foods, for example, are vegetables, fruit and grain which have been grown in soil that is rich in organic matter. In simple terms, this means that the soil has been nourished by unused vegetable matter, which provides it with essential vitamins and minerals. Natural foods also include animals which have been allowed to feed and move freely in healthy pastures. Compare this with what happens in the battery（笼式的）farms, for example, where thousands of chickens live crowded together in one building and are fed on food which is little better than rubbish. Chickens kept in this way are not only tasteless as food; they also produce eggs which lack important vitamins. There are other aspects of healthy eating. Take sugar for example. It is not that sugar is harmful in itself. But it does seem to be addictive: the quantity we use has grown steadily over the last two centuries. Yet all it does is to provide us with energy, in the form of calories. There are no vitamins in it, no minerals — and no fiber. It is significant that nowadays fiber is considered to be an important part of a healthy diet. It is interesting to note that in countries where the national diet contains large quantities of unrefined flour and vegetables, certain diseases are comparatively rare.根据短文完成1-5题，在空格处填写正确选项的字母。1. People have become more interested in natural foods because ______.A) they want a change of dietB) they want to eat food that is better for themC) they no longer like processed foods polluted by chemical additivesD) they want to be fashionable