Question

bio - 201 topic 1: anatomy, physiology, homeostasis, and the chemistry of life
practice it
the function of an enzyme is to
change the direction of a chemical reaction.
prevent a chemical reaction from occurring.
stop a chemical reaction once it has started.
speed up the rate of a chemical reaction.
increase the activation energy of a chemical reaction.

Explanation:

Enzymes are biological catalysts. Catalysts lower the activation - energy of a chemical reaction, which speeds up the rate of the reaction. They do not change the direction of a reaction, prevent it, stop it, or increase activation energy.

Answer:

speed up the rate of a chemical reaction.