The law of mass action suggests that
the higher concentration of molecules, the faster a reaction can occur
heat affects the rate of chemical reaction
equal amounts of reactants yield equal amounts of products

Explanation:

The law of mass action states that the rate of a chemical reaction is directly proportional to the product of the masses of the reactor. In other words, the more molecules concentration, the faster the reaction can develop.

Therefore, the choice that completes the given statement is the first one: "the higher concentration of molecules, the faster a reaction can occur".

So, the completed statement is The law of mass action suggests thatthe higher concentration of molecules, the faster a reaction can occur.

d. air pressure decreases as altitude increases.