Sharks help maintain the genetic health of the fish populations they feed on by eating the weak, sick and injured. They also keep their prey populations in balance.
通过吃掉老弱病残和受伤者，鲨鱼协助维持其猎物鱼群的基因健康，同时也使其数量保持平衡。
Sharks help maintain the genetic health of the fish populations they feed on by eating the weak, sick and injured.They also keep their prey populations in balance.
通过吃掉老弱病残和受伤者，鲨鱼协助维持其猎物鱼群的基因健康，同时也使其数量保持平衡。
Time was when biologists somewhat over-worded the evidence that these creatures preserve the health of game by killing the physically weak, or that they prey only on "worthless" species.
曾几何时，生物学家们有点过度使用这个证据，即这些物种通过杀死体质弱者或者仅捕食那些它们认为无价值的物种来维持食物链的正常运转。
Time was when biologists somewhat over worded the evidence that these creatures preserve the health of game by killing the physically weak, or that they prey only on "worthless" species.
曾经有段时间，生物学家或多或少滥用了一种证据，即这些生物通过杀死体弱者来保持种群的健康，或者说它们仅仅捕食没有价值的物种。
Time was when biologists somewhat over worded the evidence that these creatures preserve the health of game by killing the physically weak, or that they prey only on "worthless" species.
曾经有段时间，生物学家或多或少滥用了一种证据，即这些生物通过杀死体弱者来保持种群的健康，或者说它们仅仅捕食没有价值的物种。
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