单选题
Coincident with concerns about the accelerating loss
of species and habitats has been a growing appreciation of the importance of
biological diversity, the number of species in a particular ecosystem, to the
health of the Earth and human being. Much has been written about the diversity
of terrestrial (陆生的) organisms, particularly the exceptionally rich life
associated with tropical rain forest habitats. Relatively
little has been said, however, about diversity of life in the sea even though
coral reef systems are comparable to rain forests in terms of richness of life.
An alien exploring Earth would probably give priority to the planet's dominant,
most distinctive feature—the ocean. Humans have a bias toward land that
sometimes gets in the way of truly examining global issues. Seen from far away,
it is easy to realize that landmasses occupy one third of the Earth's surface.
Given that two thirds of the Earth's surface is water and that marine life lives
at all levels of the ocean, the total three dimensional living space of the
ocean is perhaps 100 times greater than that of land and contains more than 90
percent of all life on Earth even though the ocean has fewer distinct
species. The fact that half of the known species are thought to
inhabit the world's rain forests does not seem surprising, considering the huge
numbers of insects that comprise the bulk of the species. One scientist found
many different species of ants in just one tree from a rain forest. While every
species is different from every other species, their genetic makeup constrains
them to be insects and to share similar characteristics with 750,000 species of
insects. If basic, broad categories such as phyla and classes (门和纲) are given
more emphasis than differentiating between species, then the greatest diversity
of life is unquestionably in the sea. Nearly every major type of plant and
animal has some representation there. To appreciate fully the
diversity and abundance of life in the sea, it helps to think small. Every
spoonful of ocean water contains life on the order of 100 to 100, 000 bacterial
cells plus assorted microscopic plants and animals, including larvae (幼虫) of
organisms ranging from sponges and corals to starfish and clams and much
more.
单选题
The main topic of the passage is that ______.
A. humans are destroying thousands of species
B. there are thousands of insect species
C. the sea is even richer in life than the rain forests
D. coral reefs are similar to rain forests
【正确答案】
C
【答案解析】主旨题。综观全文，本文的主题是海洋中的生物比热带雨林中的丰富得多。
单选题
The author compares rain forests to coral reefs because ______.
A. they are approximately the same size
B. they share many similar features
C. most of their inhabitants require water
D. both have many different forms of life
【正确答案】
D
【答案解析】推理题。根据第二段第一句中，作者指出就生物种多样性而言，珊瑚礁和热带雨林可堪相比。
单选题
The passage suggests that most rain forest species are ______.
A. insects
B. bacteria
C. mammals
D. birds
【正确答案】
A
【答案解析】细节题。根据第三段第一句，热带雨林中的主要物种是昆虫。
单选题
The author argues that there is more diversity of life in the sea than
in the rain forests because ______.
A. more phyla and classes of life are represented in the sea
B. there are too many insects to make meaningful distinctions
C. many insects species are too small to divide into categories