A higher concentration of molecules causes a fast chemical reaction. This is know as

A) the law of mass action

B) chemical equilibrium

C) activation energy

D) metabolism

This is known as chemical equilibrium.

A

Explanation:

A - The law of mass action is defined as "the principle that the rate of a chemical reaction is directly proportional to the concentrations of the reacting substances". This means that as the concentration of the substrates are increased, the rate of the reactions also increases.

Chemical equilibrium is where the products are being formed as fast as the are turned back into the substrate.

Activation energy is the energy needed to start a chemical reaction.

Metabolism is the rate at which chemicals (specifically in the body) are broken down.