本题目来源于试卷: Biodiversity，类别为 IB环境系统与社会
[单选题]
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Explain the high habitat diversity found in a tropical rainforest.
A. The vegetation in tropical rainforests has a complex vertical structure with many layers. This leads to many niches and, thus, high habitat diversity.
B. Tropical rainforests have high insolation and rainfall throughout the year, leading to high productivity and, thus, high habitat diversity.
C. Tropical rainforests have deep and fertile soil layers allowing for tall trees' growth. This leads to many niches and, thus, high habitat diversity.
D. Tropical rainforests are found chiefly at sea level, so problems associated with high altitude do not affect the habitat diversity.
参考答案: A
本题详细解析:
Tropical lowland rainforests occur from r,je kvk6 z v8mg/wa13sea level up to about 1500
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m in altitude, so option D is incorrect because it states that they occcur at sea level. The difference in altitude and the variation in terrain with hills and mountains lead to higher habitat diversity.
Tropical rainforests may have deep soil layers in places, but they tend to be relj186kv,zv /g w r3keamatively infertile. Only the thin top layer of decaying biomatter provides the nutrients for many plants to grow. Moreover, high productivity of plants does not lead to habitat diversity; it simply results in a high quality of the habitat, making it easier for species adapted to that habitat to do well. Thus option C is incorrect.
Option B is incorrect for similar reasons to option C; higher productivity does not necessarily lead to higher habitat diversity.
Option A is correct because the many layers in the tropical rainforest are, in fact, so different that they are different habitats. Each layer has different insolation and rainfall levels; even the temperature will vary from the top of a tree down to the forest floor as the sunlight is filtered.
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