( 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（琏）. 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 goes away.
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 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 cannot 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.
（ ）6. 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.
( ) 7. Which living things can use the sun’s energy directly?
A. Animals B. plants
C. Both animals and plants D. All living things
( ) 8. What do plants make food from? They make food from___.
A. Sunlight, water and things in the soil and air
B. Sunlight, water and things in the soil
C. Water and things in the soil and air
D. Sunlight, water and things in the air
( ) 9. Who often breaks up the food chains?
A. Human beings B. Animals
C. Plants and animals D. Men and wild animals
( ) 10. Which do you think is the best title of this passage?
A. Animals B. Plants C. Food D. Living things