Question

a substance that influences the reaction but does not participate in the reaction is a catalyst reactant product substrate

Explanation:

A catalyst speeds up a chemical reaction by providing an alternative reaction pathway with a lower activation energy, without being consumed in the reaction. Reactants are substances that participate in the reaction to form products. Products are the substances formed from the reaction. A substrate is a substance on which an enzyme acts in a biochemical reaction.

Answer:

A. catalyst