题目解析:
D 用different species定位到原文倒数第二、三句话: Competition among the individuals of different species (interspecies competition) is a major concern of ecology.It is one of the factors controlling the size of competing populations, and extreme cases it may lead to the extinction of one of the competing species.这里明确说了,这是对于竞争种群的一种控制,极端情况下可能会使其中一个竞争物种灭绝。所以,对应D选项的control。ABC选项都没有提及。