Enzymes are added to a chemical reaction to lower the activation energy. what is an enzyme classified as?
a) a catalyst
b) an inhibitor
c) an accelerator
d) a depressant

A) a catalyst

Explanation:

A) Enzymes are also called as bio catalysts and thus increases the rtae of reaction in living beings.

A catalyst is a substance which increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more molecules can cross the energy barrier and convert to products.

B) An inhibitor  decreases the rate of reaction.

C) an accelerator  increases the rate of reaction.

D) a depressant decreases the rate of reaction.