Camouflage
Camouflage is one of the most effective ways for animals to avoid attack in the treeless Arctic. However, the summer and winter landscapes there are so diverse that a single protective coloring scheme would, of course, prove ineffective in one season or the other. Thus, many of the inhabitants of the Arctic tundra change their camouflage twice a year. The arctic fox is a clear-cut example of this phenomenon; it sports a brownish-gray coat in the summer which then turns white as cold weather sets in, and the process reverses itself in the springtime. Its brownish-gray coat blends in with the barren tundra landscape in the months without snow, and the white coat naturally blends in with the landscape of the frozen wintertime tundra.
1. Which of the sentences below expresses the essential information in the first highlighted sentence in the passage?
Incorrect choices change the meaning in important ways or leave out essential information.
A. Opposite conditions in summer and in winter necessitate different protective coloration for Arctic animals.
B. The coloration of the summer and winter landscapes in the Arctic fails to protect the Arctic tundra.
C. In a single season, protective coloring scheme are ineffective in the treeless Arctic.
D. For many animals, a single protective coloring scheme effectively protects them during summer and winter months.
答案:A
2. Which of the sentences below expresses the essential information in the second highlighted sentence in the passage?
Incorrect choices change the meaning in important ways or leave out essential information.
A. The arctic fox is unusual in that he color of its coat changes for no reason.
B. The arctic fox lives in an environment that is brownish gray in the summer and white in the winter.
C. It is a phenomenon that the coat of the arctic fox turns white I the springtime and gray in the fall.
D. The arctic fox demonstrates that protective coloration can change during different seasons.
答案:D