You are presented with the quiz "Cells are the basic units allowing what in all living things" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "cells are the basic units of the structure and function of living things" and "respiration is a function of life, which means it is carried on by all living things". 

So, what's the best answer to the question?


 

      respiration     