...and ensures it has reserves to get through leaner times. 并能够有所储备 以便挺过食物较少的时期
a behavior that ensures the survival of the fittest. 这种行为能够确保最优秀者生存下来
ensures that his newly hatched young will never go hungry. 以确保刚出生的幼鸟不会挨饿
The competition for resources ensures that no one species dominates the jungle. 雨林中激烈的资源竞争 使得没有哪个物种可以统治这块地方
The relentless power of the wind ensures that the face of a desert is continually changing. 风的无情力量总是使沙漠的面貌不断改变