【备考每日练】GRE阅读题之环境保护问题

北京GRE培训,GRE备考资料,GRE网课,GRE培训机构,GRE保分班,GRE真题,GRE课程

名师心血之作，考生必备最完美阅读资料，让GRE阅读更加完美，打造你的完美GRE分数，走过路过不要错过，命运掌握在自己手中，GRE掌握在自己手中，每日练一练，分数节节高，你值得拥有，且看且珍惜!GRE必胜!

每日一练

Although pathogenic organisms constantly alight on the skin, they find it a

very unfavorable environment and, in the absence of injury, have great

difficulty colonizing it. This “self-sterilizing” capacity of the skin results

from the tendency of all well-developed ecosystems toward homeostasis, or the

maintenance of the status quo.

Species that typically live in soil, water, and elsewhere rarely multiply on

the skin. Undamaged skin is also unfavorable to most human pathogens. The skin

is too acid and too arid for some species. The constant shedding of the surface

skin layers further hinders the establishment of invaders. The most interesting

defense mechanism, however, results from the metabolic activities of the

resident flora. Unsaturated fatty acids, an important component of the lipids in

sebum collected from the skin surface, inhibit the growth of several bacterial

and fungal cutaneous pathogens. These acids are a metabolic product of certain

gram-positive members of the cutaneous community, which break down the more

complex lipids in freshly secreted sebum.

1. The primary purpose of the passage is to

A. Offer an analysis of metabolic processes

B. detail the ways in which bacteria and fungi can be- inhibited

C. Describe mechanisms by which the skin protects itself against

pathogens

D. Analyze the methods whereby biological systems maintain the status quo

E. Provide a specific example of the skin’s basic defenses against

pathogens

2. The “resident flora” refers to

A. “Unsaturated fatty acids”

B. “sebum collected from the skin surface”

C. “bacterial and fungal cutaneous pathogens”

D. “certain gram-positive members of the cutaneous community”

E. “more complex lipids”

3. The author presents her material in which of the following ways?

A. Stating a problem and then supplying a solution

B. Presenting a phenomenon and then analyzing reason font

C. Providing information and then drawing a conclusion from it

D. Making a general statement and then arguing by analogy

E. Making an inference and then developing it by illustration

正确答案

C D B

认真看完题目的考生，请允许小编为你狠狠鞠上一躬，征服美利坚不是梦啊!希望每位考生在考前都能做好充分的准备，得到自己理想的分数!

2015年最新GRE阅读每日一练(12月4日)

2015年最新GRE阅读每日一练(12月3日)