2019年10月12日托福阅读真题+题目+答案：Insect Wings

2019年10月12日托福阅读真题+题目+答案：Insect Wings

The power of flight is a major chapter in the success story of insects. Because insects with developed wings appear relatively suddenly in the fossil record and there are no good fossils that show intermediate stages, there is a great deal of speculation as to how wings might have evolved.

Insects are different from other flying creatures like birds and bats, which evolved wings from already existing legs, and one of the main questions is what the first protowings (early forms of wings) were used for. ▋One view is that outgrowths from the notum (upper portion) of the thorax (middle region of the body between the head and the abdomen) would have enabled insects to have a more stable and longer glide path (movement through the air without using wings). ▋This paranotal theory envisages early insects climbing plants and launching themselves into the air as a more efficient, and perhaps safer, means of getting around or avoiding predators.▋ These protowings might have had other functions, and experimental evidence suggests that when small, they would have had a significant role in the regulation of body temperature.▋ Other ideas have involved small insects being carried around in air currents or larger insects jumping from the ground and taking to the air.

1.According to paragraph 2, one benefit of the outgrowths from an insect’s thorax might have been to

A.allow the insect to sense the presence of predators

B.prevent the insect from being carried away by air currents

C.allow the insect to glide through the air for a longer distance

D.aid the insect in climbing up plants

There is a major problem with ideas that involve paranotal protowings and gliding, which is that, at some time, these fixed structures needed to have become hinged (connected in a way that allows on structure to swing relative to the other) and to have developed muscle systems to make them flap up and down. It is much easier to imagine structures that were already hinged and muscled in fulfilling some prior function and then eventually taking on a role in flight. The endite-exite theory suggests that protowings developed from the fusion of inner and outer appendages (endites and exites) of short leg segments, which were already hinged and might have been under some sort of muscular control.

2.The word “fulfilling” in the passage is closest in meaning to

A.performing

B.developing

C.replacing

D.combining with

3.The word “function” in the passage is closest in meaning to

A.plan

B.role

C.form

D.habit

4.Which of the following best describes the “endite-exite theory”?

A.Hinges on leg appendages evolved from paranotal protowings.

B.The development of muscle systems led to the evolution of short leg segments.

C.Wings grew outward from the end of flap-like structures on the body.

D.Protowings evolved from the joining of inner and out parts of legs.

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