In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
One example: The Inheritance Cycle is a series of fantasy books written by Christopher Paolini.
Solution is here: The Inheritance Cycle is a tetralogy of young adult high fantasy novels written by American author Christopher Paolini.
Explanation: The output sentence elaborates on the input sentence without changing its general meaning e.g. "tetralogy of young adult high fantasy novels".

Now, solve this: Population declines and , as smaller animals need fewer resources and smaller territories , they will survive longer .
Solution:
The smaller animals need fewer resources and smaller territories , and so are more likely to get past the break-point where population decline allows food sources to replenish enough for the survivors to flourish .