Question

multiple-choice question
what do enzymes do?
they slow down chemical reactions.
they speed up chemical reactions.
rewatch

Explanation:

Enzymes are biological catalysts. Catalysts increase the rate of chemical reactions without being consumed in the process. So enzymes speed up chemical reactions, while substances that slow down reactions are called inhibitors, not enzymes.

Answer:

B. They speed up chemical reactions. (assuming the second option is labeled B; if the first option was A and the second B, the correct one is the second option stating they speed up chemical reactions)