Question

which organisms characteristically undergo anaerobic respiration

Answer 1

yeast, for example, turns the sugar in beer into delicious ethanol.

I'm not sure about that: every higher evolved organism has to do aerobic respiration at laest partly. correct me, if I am wrong, but that makes sense to me.

now, all anaerobic bacteria (like e. coli) do anaerobic respiration, which is not as effective as aerobic respiration.