You are presented with the quiz "Why do cells secrete acids?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "cells secrete acids and bases to maintain the proper pH for enzymes to work" and "enzymes help to break down proteins so that the bacteria can do their thing better". So, what's the best answer to the question?

Select from the following. (i). Make money (ii). resistance activities (iii). allow growth (iv). Plant growth is reduced (v). Break down proteins (vi). Hurt things (vii). increases a body's strength (viii). Help friends
The answer is:
(v).