Given a scientific question, generate a correct answer to it.

[EX Q]: Herbivores are heterotrophs that eat only or mainly what?
[EX A]: plants

[EX Q]: Electrons in covalent compounds are shared between the two atoms, unlike the case in what type of bonds?
[EX A]: ionic bonds

[EX Q]: What is a copy of an image formed by reflection or refraction?
[EX A]:
an image