来源:西安中考网 作者:西安中考网编辑 2012-09-27 11:04:29
B
All living things on the earth need other living things to live . Nothing lives alone . Most animals must live in a group , and even a plant grows close together with others of the same kind . Sometimes one living thing kills another , one eats and the other is eaten . Each kind of life eats another kind of life in order to live , and together they form a food chain(食物链). Some food chains are simple , while others are not . But all food chains begin with the sun , and all food chains become broken up if one of the links disappears.
All life needs sunlight to live on . But only plants can use sunlight directly . Plants are “factories”. They make food from sunlight , water and things in the soil and air.
Plants feed all other living things . Animals can only use the sun’s energy (能量)after it has been changed into food by plants . Some animals feed directly on plants ,others eat smaller animals . Meat-eating animals are only eating plants indirectly .
What about human beings ? We are members of many food chains . We eat wheat , rice , vegetables , fruits and so on . We also eat meat and drink milk . But men often break up the food chains . They kill wild animals . They also make rivers , lakes and seas dirty . When these rivers , lakes and seas are polluted , the fish in them can not be eaten . If men eat the fish , they will get strange diseases.
Each form of life is linked to all others . Breaking the links puts all life in danger.
46. How does every living thing on the earth live ?
A. Each plant can live alone.
B. Each animal can live alone.
C. If living things want to live , they must kill each other.
D. Every living thing on the earth cannot live without others.
47. Which living things can use the sun’s energy directly ?
A. Animals. B. Plants C. Both animals and plants D. All living things.
2018年西安中考各科真题及答案 | ||||
语文 | 数学 | 英语 | 理化 | 政史 |
2023中考一路陪伴同行,百万名校真题直接下载!>>点击查看