The destruction of habitats(栖息地)all over the world is the primar

The destruction of habitats(栖息地)all over the world is the primary reason species are?becoming extinct(灭绝)or endangered．Houses,highways,dams,industrial buildings,and?ever-spreading farms now dominate?21?formerly occupied by forests,deserts,and wetlands．22?the beginning of European settlement in America,23, over 65,000,000 acres of?wetlands have been drained．One million acres alone vanished 24?1985 and 1995． Habitat destruction can be?25?or it can be subtle,occurring over a 26?period of time?without being noticed．27?such as sewage from cities and chemical runoff fromfarms,can change?the?28?and quantity of water in streams and rivers．To?29?living in a delicately balanced?habitat,this disturbance can be as 30?as the clear-cutting of a rainforest． 31?remaining habitats are carved into smaller and smaller pockets or islands,remaining?species are forced to exist in these?32?areas,which causes further habitat?33?These?species become less adaptable to environmental?34；in fact,they become?35?endangered．Scientists believe that when a habitat is cut by 90%,one-half of its plants,animals and insects will?become extinct． 第29题的答案是（ ）
A、people
B、Species
C、plants
D、insects
【正确答案】：B
【题目解析】：第29题所在句子的完整内容为：“To 29 living in a delicately balanced habitat, this disturbance can be as 30 as the clear-cutting of a rainforest.” 这句话讨论的是栖息地的微妙变化如何对生活在其中的生物造成影响。 选项A“people”指的是人类，但在该句中，并未特别指向人类，而是泛指生活在微妙平衡栖息地中的生物。 选项B“Species”指的是物种，这与句子描述的“生活在微妙平衡栖息地中的生物”相吻合，是一个更泛指的词，能够涵盖多种生物。 选项C“plants”和选项D“insects”分别指的是植物和昆虫，这两个选项虽然也是生物的一种，但在这里，它们只代表了生物的一部分，不如“Species”这个词全面。 考虑到该句子的语境和要表达的意思，最合适的答案是B“Species”。这个答案能够最好地表达出栖息地微妙变化对所有生活在那里的物种造成的影响，而不仅仅是人类、植物或昆虫。因此，正确答案是B。