确定每一个营养阶层原生质总量的第二个好办法是称重。
The next best way to quantify the amount of protoplasm in each trophic level is to weigh it.
天敌搜寻食物的行为依赖于来自不同营养阶层上的信息，化学信息起重要作用。
Hunting food behavior of natural enemy depends on information from various trophic levels, especially chemical information.
我所谓的贫穷是指各阶层知识上的贫穷、无法为家庭提供营养的菜单。
It is a poverty of being able to nourish their family, in any class.
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