新GRE小短文阅读练习题七

会计考友

7   During the day in Lake Constance, the zooplankton  D.  hyalina departs
for the depths where food is scarce and the water cold.   D.  galeata
remains near the warm surface where food is abundant.  Even though
  p* n+ a- T  i. J8 ^1 ~ D. galeata grows and reproduces much faster, its population is often
outnumbered byD. hyalina.

Which of the following, if true, most helps to resolve the apparent
1 z! j6 ]7 o% Y( t" p paradox?
. l! b- p" d4 D; I- ~
' G. D5 S3 D& U: R5 C4 ]" j6 F7 I       The number of species of zooplankton living at the bottom of the
        lake is  twice that of species living at the surface.  
       Predators of zooplankton, such as whitefish and perch, live and
) z( B8 {* J! L& N        feed near the surface of the lake during the day.  
$ e3 D! x5 i; |, P8 i; O       In order to make the most of scarce food resources,  D.  hyalina
- ^8 G0 K" P& V        matures more slowly than  D.  galeata .  
       D.  galeata  clusters under vegetation during the hotest part of
4 q: R; Q0 P: \1 j7 w8 Y4 ^- h        the day to avoid the Sun's rays.  
       D.  galeata  produces    twice as many offspring per individual in
, q. g5 o4 e7 L+ C5 r0 D        any given period of time as does    D. hyalina.