Eco-Systems may vary in size true or false

True. (sorry if its wrong)

Explanation:

The size of an ecosystem varies depending on how you define it. Ecosystems are in indefinite sizes. It can exist in a small area, such as under a rock, a decaying tree trunk or a pond in a nearby town. It can also exist as a large form, such as a whole rain forest.

c is the answer for this

answer; authoritative;