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D
What is a food chain? Every living thing needs energy. How they get energy depends on what kind of living things they are. All food chains have producers, consumers and decomposers. To understand a food chain, follow the path of how plants and animals get their energy.
Producers make their own food. Consumers need to eat to get energy. Some consumers eat producers. Some consumers eat other consumers. Decomposers play the final role in a food chain. Decomposers break down dead plants and animals.
Food chains are different depending on the habitats in which the living things exist. The habitat can be a woodland, a garden or a sea. All parts of a food chain are important for keeping a habitat healthy. Food chains usually start with a green plant. This is because plants often use sunlight to make their own energy.
Arctic (北极的) food chains
Arctic food chains can include both land and sea animals.
A polar bear is at the top of an Arctic food chain. The polar bear eats a seal (海豹). The seal eats small shrimp (虾). The shrimp feed on tiny ocean plants. Polar bears, seals and shrimp are all consumers. These ocean plants are producers. Ocean decomposers include sea cucumbers and bacteria (细菌).
Desert food chains
Desert habitats are hot and dry. The producers, consumers and decomposers in the desert must survive this weather.
An example of a desert food chain from the top starts with a mountain lion. The mountain lion eats a rabbit. The rabbit eats the desert grass. Bacteria break down waste. Another food chain begins with cacti (仙人掌). Then there is a mouse. Then there is a fox. A mountain lion might eat the fox.
(
A. Places. B. Animals. C. Plants. D. Symbols.
(
A. Types of trees. B. All the animals.
C. Who eats whom. D. Where to live.
(
A. Cacti→mouse→fox. B. Sunlight→tree→sea star.
C. Lion→grass→rabbit. D. Polar bear→shrimp→seal.
(
A. If there is no rabbit, there will be no snake.
B. Humans can still live happily without plants.
C. There will be fewer food chains in the world.
D. Every food chain shows how energy moves.
What is a food chain? Every living thing needs energy. How they get energy depends on what kind of living things they are. All food chains have producers, consumers and decomposers. To understand a food chain, follow the path of how plants and animals get their energy.
Producers make their own food. Consumers need to eat to get energy. Some consumers eat producers. Some consumers eat other consumers. Decomposers play the final role in a food chain. Decomposers break down dead plants and animals.
Food chains are different depending on the habitats in which the living things exist. The habitat can be a woodland, a garden or a sea. All parts of a food chain are important for keeping a habitat healthy. Food chains usually start with a green plant. This is because plants often use sunlight to make their own energy.
Arctic (北极的) food chains
Arctic food chains can include both land and sea animals.
A polar bear is at the top of an Arctic food chain. The polar bear eats a seal (海豹). The seal eats small shrimp (虾). The shrimp feed on tiny ocean plants. Polar bears, seals and shrimp are all consumers. These ocean plants are producers. Ocean decomposers include sea cucumbers and bacteria (细菌).
Desert food chains
Desert habitats are hot and dry. The producers, consumers and decomposers in the desert must survive this weather.
An example of a desert food chain from the top starts with a mountain lion. The mountain lion eats a rabbit. The rabbit eats the desert grass. Bacteria break down waste. Another food chain begins with cacti (仙人掌). Then there is a mouse. Then there is a fox. A mountain lion might eat the fox.
(
A
) 25. What does “habitats” in Paragraph 3 refer to?A. Places. B. Animals. C. Plants. D. Symbols.
(
C
) 26. According to the passage, what is a food chain?A. Types of trees. B. All the animals.
C. Who eats whom. D. Where to live.
(
A
) 27. Which of the following can be part of a food chain?A. Cacti→mouse→fox. B. Sunlight→tree→sea star.
C. Lion→grass→rabbit. D. Polar bear→shrimp→seal.
(
D
) 28. What can you learn from the passage?A. If there is no rabbit, there will be no snake.
B. Humans can still live happily without plants.
C. There will be fewer food chains in the world.
D. Every food chain shows how energy moves.
答案
25. A 26. C 27. A 28. D
