Question

Which is a characteristic of bacteria?

A. They are unicellular.B. They are eukaryotic.C. They are multicellular.D. They are always harmful.

Answer 1

Well we can already narrow it down. Obviously, not all bacteria are harmful, so D is definitely out. Bacteria are not eukaryotic either, they are prokaryotic. Bacteria not multicellular, so the answer is not C either.
B, C, and D are out of the game, so the answer is A, they are unicellular.

The definition of bacteria: Domain of unicellular prokaryotes that have cell walls containing
peptidoglycan; corresponds to the kingdom eubacteria.

Answer 2

thanks