Ahigher concentration of molecules causes a faster chemical reaction. this is known as

Law of mass action

Explanation:

According to the law of mass action, the rate at which a chemical reaction takes place depends on the concentration of the reactants. The higher the concentration of the reactants the higher will be the rate of reaction and thus more product will be formed

Or in other way it can be said that the rate of formation of any product through any  chemical reaction is directly proportional to the concentration of the reactant.  

what is the aerea shown

explanation:

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.