During the day in Lake Constance, the zoo-plankton D. hyalina departs for the depths where food is scare and the water cold. D. galeata remains near the warm surface where food is abundant. Even though D. galeata grows and reprocess much faster, its population is often outnumbered by D. hyaline. Which of the following, if true, would help resolve the apparent paradox presented above? (A) The number of species of zooplankton living at the lakes is twice that of species living at the surface. (B) Predators of zooplankton, such as white-fish and perch, live and feed near the surface of the lake during the day. (C) In order to make the most of scare food resources, D. hyaline matures more slowly than D. galeata. (D) D. galeata clusters under vegetation during the hottest part of the day to avoid the sun’s rays. (E) D. galeata produces twice as many offspring per individual in any period of time does D. hyalina.
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发表于 2008-8-25 17:54:00
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