2014年4月19日托福阅读真题P2+题目+答案：Distribution of Seaweeds

2014年4月19日托福阅读真题P2+题目+答案：Distribution of Seaweeds

Seaweeds are multicellular algae that inhabit the oceans. Despite their evolutionary distance from each other, seaweeds—such as brown algae, red algae, and green algae—have in common many aspects of their biology and contributions to the ecology of the seas.

Most species of seaweed are benthic (living on the seafloor); they grow on rock, sand, mud, and coral on the sea bottom. Other species live on other organisms and as part of fouling communities (plants and animals that live on pilings, boat bottoms, and other artificial surfaces). Some seaweeds attach to very specific surfaces, whereas other seaweeds are rather nonselective. In general, seaweeds inhabit about 2 percent of the seafloor. The presence of benthic seaweeds defines the inner continental shelf, where the marine community largely depends on the food and protection that seaweeds provide. Life on the outer continental shelf and in the deep sea is quite different in the absence of seaweeds. The distinction between the inner and outer shelves is based on the compensation depth of algae. The compensation depth is the depth of water at which there is just enough light for algae to survive. At that depth all the oxygen produced by photosynthesis is consumed by the algae’s respiration, so that no further growth can occur.

1. The word “artificial” in the passage is closet in meaning to

A.suitable

B.human-made

C.uneven

D.available

2. What can be inferred from paragraph 2 about the outer continental shelf?

A.The outer continental shelf contains more benthic seaweeds than the deep sea does.

B.The outer continental shelf lacks enough sunlight to support the growth of algae.

C.The outer continental shelf has a compensation depth that is about the same as that of the inner continental shelf.

D.The outer continental shelf has a greater variety of marine life than does the inner continental shelf.

3. According to paragraph 2, all of the following are true of seaweeds EXCEPT:

A.Seaweeds provide food and protection for other organisms.

B.Seaweeds can grow on both living and nonliving things.

C.Some seaweeds select specific surfaces to attach to, while others are not selective.

D.Two percent of seaweed species live on the ocean floor.

The environmental factors that are most influential in governing the distribution of seaweeds are light and temperature. Some other abiotic (nonliving) factors critical in governing the distribution of seaweeds are duration of tidal exposure and desiccation (drying out), wave action and surge, salinity, and availability of mineral nutrients. The areas of the world most favorable to seaweed diversity include both sides of the North Pacific Ocean, Australia, southwestern Africa, and the Mediterranean Sea.

4. The word “duration” in the passage is closet in meaning to

A.frequency

B.force of impact

C.length of time

D.occurrence

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