2015年5月30日托福阅读真题+题目+答案：Thermal Stratification

2015年5月30日托福阅读真题+题目+答案：Thermal Stratification 

1. Physical characteristics of aquatic environments at different depthssuch as salt level, light, inorganic nutrients, degree of acidity, and pressureall play key roles in the distribution of organisms. One of the most important physical features is thermal stratification.

2. When solar radiation strikes water, some is reflected, but most penetrates the surface and is ultimately absorbed. ■Although water may appear transparent, it is much denser than air and absorbs radiation rapidly. ■In clear water, 99 percent of the solar radiation is absorbed in the upper 50 to 100 meters. ■Longer wavelengths of light are absorbed first; the shorter wavelengths (which have more energy) penetrate farther, giving the depths their characteristic blue color.■

3. This rapid absorption of sunlight by water has two important consequences. First, it means that photosynthesisthe process by which plants use the energy of sunlight to produce the organic carbon compounds necessary for lifecan only occur in surface waters where the light intensity is sufficiently high. Species that produce their own organic carbon compounds are called primary producers, and they are the base of the marine food web. Virtually all of the photosynthesis that supports the rich life of oceans and lakes comes from plants living in the upper 10 to 30 meters of water. Along shores and in very shallow bodies of water, some species such as kelp are rooted to the bottom. These plants may attain considerable size and structural complexity, and may support diverse communities of organisms. In the open waters that cover much of the globe, however, the primary producers of organic carbon are tiny, often one-celled algae (called phytoplankton), which are suspended in the water. Zooplankton, tiny invertebrates that feed on phytoplankton, migrate vertically on a daily cycle: up into the surface waters at night to feed and down into the dark, deeper waters during the day to escape predatory fish that rely on light to detect prey.

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托福阅读真题题目：

1..The word ultimately in the passage is closest in meaning to

A. probably

B. quickly

C. eventually

D. frequently

2..According to paragraph 2, which of the following is true about solar radiation when it strikes water

A. Longer wavelengths travel farther.

B. Most of it is absorbed near the surface.

C. It is not absorbed by cloudy water.

D. More long wavelengths than short wavelengths are absorbed.

3..The word Virtually in the passage is closest in meaning to

A. Apparently

B. Usually

C. Nearly

D. Fortunately

4..According to paragraph 3, all of the following are true of kelp EXCEPT:

A. They are found at the bottom of shallow waters.

B. They are the primary producers of organic carbon.

C. They can grow very large.

D. They are a source of food for a variety of organisms.

5..The word suspended in the passage is closest in meaning to

A. dissolved

B. floating

C. invisible

D. released

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2015年5月30日托福阅读真题+题目+答案：Thermal Stratification ，完整版下载，10元有偿！