Fact 1: Cells secrete acids and bases to maintain the proper pH for enzymes to work. Fact 2: Enzymes help to break down proteins so that the bacteria can do their thing better. Given the two facts above, why do cells secrete acids?

(1). Make money; (2). resistance activities; (3). allow growth; (4). Plant growth is reduced; (5). Break down proteins; (6). Hurt things; (7). increases a body's strength; (8). Help friends;
The answer is:
(5).