What does it mean to define "boundaries" of an ecosystem?

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.

the fossil record provides evidence of a common ancestor to many species.

the answer is c. it will give up it's valence electron to the other atom.