2015年7月5日托福阅读真题+题目+答案：Primitive and Advanced Termite Species

2015年7月5日托福阅读真题+题目+答案：Primitive and Advanced Termite Species

1. Termites are insects that collect vegetation, chew it up, and leave the chemical breakdown to other organisms. There are two strategies. The most primitive termites swallow the chewed vegetation and pass it to a fermentation chamber in their bodies. There, anaerobic bacteria break down the cellulose, an organic compound that forms about 33 percent of all plant matter. The termites are nourished by the ever-growing population of microorganisms in their guts that turn the grass, leaves, and twigs the insects ingest into glucose. Cattle do much the same thing: they allow bacteria to ferment the cellulose in an airtight rumen (digestive chamber), and then digest the bacteria.

2. Termite evolution has several obvious trends, from primitive species, which live in small hidden colonies, to groups millions strong, the builders of enormous mounds that allow for heat and gas exchange. The less advanced groups digest microorganisms, which do the real work of breaking food down. The culture (colony) of cellulose digesters is passed along through a special exchange. Young termites feed on a special liquid secretion provided by adults, rich in the group's digestive heritage. When reproductive termitesthose destined to produce offspringleave the nest, they carry in their stomachs the microorganisms essential for the digestive success of their offspring. Treat a colony of these termites with an antibiotic solution, and they will slowly starve to death.

3. More advanced species have a different feeding strategy. The energy source is still cellulose, but it is digested outside the termite's body. Not having to carry around large chambers of slowly fermenting cellulose solution makes these species more nimble and efficient. Foragers bring twigs and leaves back to special areas and chew them. They then transplant bits of fungus growing on other pieces of nearby vegetation onto the gnawed edges, where the fungi break down the cellulose. Fungi is the only kingdom of organisms able to digest cellulose in air, though they need warmth and humidity to do the job efficiently. This is just what the termites provide. Moreover, these social insects carefully tend the fungus-covered vegetation by treating it with antibiotics they secrete to keep bacterial growth to a minimum. When it is time for the fungus to reproduce, pieces are carried into the open to complete the life cycle. Some species of fungi are found only in termite mounds of a particular species; without their caretakers, these fungi would die. Needless to say, the termites eat the fungi; neither can live without the other. Reproductive termites even carry a chunk of fungi when they leave on mating flights.

。。。。。此处省略余下原文！

托福阅读真题题目：

1..According to paragraph 1, in what way are the most primitive termites like cattle

A. They have two ways of breaking down the cellulose in vegetation.

B. They get no nutritional benefit from eating vegetation.

C. Their digestive chambers are not airtight.

D. They rely on bacteria to process the vegetation they ingest.

2..The phrase special exchange in the passage refers to

A. the transfer of cellulose digesters from one colony of termites to another

B. the development of small colonies into much larger ones

C. the transfer of liquid secretions from adult termites to young termites

D. the departure of certain reproductive termites and the arrival of others

3..Why does the author include the statement Treat a colony of these termites with an antibiotic solution, and they will slowly starve to death

A. To suggest one reason why termites sometimes leave a colony

B. To emphasize how dependent the termites are on bacteria

C. To account for the elimination of certain termite lineages

D. To help explain why termites protect essential microorganisms by carrying them in their stomachs

4..The phrase Needless to say in the passage is closest in meaning to

A. On the other hand

B. Most importantly

C. Obviously

D. Besides

。。。。。此处省略余下题目和答案！

2015年7月5日托福阅读真题+题目+答案：Primitive and Advanced Termite Species，完整版下载，10元有偿！