新GRE小短文阅读练习题十六

会计考友

16  Why save endangered species?  For the general public, endangered
( T* M4 r/ S9 y/ tspecies appear to be little more than biological oddities.  A very dif-
6 B5 v* Y% O% `' ^! Kferent perception is gained from considering the issue of extinction in a
wider context.  The important point is that many major social advances
have been made on the basis of life forms whose worth would never have
( h3 f, f3 B7 }8 W! jbeen perceived in advance.  Consider the impact of rubber-producing
plants on contemporary life and industry:  approximately  two-thirds of the
* u: b( O4 B$ B4 l0 ~! f0 M/ [world's rubber supply comes from rubber-producing plants and is made
into objects as diverse as rubber washers and rubber boots.

( f5 L* e3 t: f2 _% p' m$ B: SAny of the following facts could be used as illustrative examples in addi-
4 r+ K& Z* b' P4 C5 [( V/ Ation to the example of rubber-producing plants EXCEPT:

      The discovery of the vaccine for smallpox resulted from observing
        the effect of the cowpox virus on the hands of dairy workers.  
      The major source of our pharmaceutical supplies is plants, some of
        them commonly thought of as weeds.  
: o) d  f# h/ F4 v" [/ a      Certain antibiotics were originally derived from mold growing on
- u% _+ {; b2 k$ j8 `        cantaloupes.  
7 x% f4 O  f6 A* Z9 E      Plastic is a unique product derived from petroleum and petroleum by-
' l& n, v, _! G  f        products.  
      Hamsters and other rodents have played an important role in labo-
1 ]3 a  _# ~0 D2 S  h- X        rator y tests of medicine for use on humans.