An intrinsic property of all natural and complete ecosystem, is

Answer: Option A

An intrinsic property of a natural and complete ecosystem, is Self-sustainability.
Self-sustainability and self-sufficiency are overlapping states of being in which a person or an organization needs little or no help from, or interaction with, others. Self-sufficiency entails the self being enough, and a self-sustaining entity can maintain self-sufficiency indefinitely.
It is a type of sustainable living in which nothing is consumed other than what is produced by self-sufficient individuals.