三岔湖是四川第二大湖泊，下列描述中属于生态系统的是（ ）
A．湖中的全部水
B．湖中的全部鲤鱼
C．湖中的全部水草
D．整个湖泊
A、湖中的全部水，只是非生物部分的一部分，没有生物部分，不能构成一个完整的生态系统，A错误．
B、湖中的全部鲤鱼，只包括了生物部分的部分动物，没有其它生物，也没有非生物部分，不能构成一个完整的生态系统，B错误．
C、湖中的全部水草，只是生物部分中的植物，没有其它生物以及非生物部分，不能构成一个完整的生态系统，C错误．
D、整个湖，既包括了这湖所在的环境，又包括了此环境中的所有生物，符合生态系统的概念，D正确．
故选：D
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| Suppose (假定) every person on Earth ate only one kind of food. And maybe one year that food couldn't 1 . If that happened, man would soon 2 . Luckily, man doesn't 3 that problem. But another animal may. The animal is the giant (巨大的) panda, one of the world's most-loved animals. Dr Thomas Soderstrom, a scientist, has 4 for the first time that thebamboo (竹子) the giant pandas eat is dying. As a result, many of the pandas are also dying of being 5 . Scientists estimate (估计) that so far more than 140 giant pandas have died. This number may be 6 one-quarter of the world's giant panda population. Between 400 and 1000 giant pandas are 7 to live in mountains. Giant pandas were once more 8 all over many parts of Asia (亚洲). Now they are only in small parts of China. Can the wild pandas be 9 ? The scientists want to find out more about the animals' food. They want to see whether the pandas are able to 10 their food while the bamboo is dying. Chinese scientists are trying to raise (饲养) more pandas in zoos. The first baby panda was born in the Beijing Zoo in the fall of 1978. | ||||
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