Catalysts increase the rate of a reaction by

By lowering the activation energy.

Explanation:

A catalyst refers to a substance, which enhances the rate of a chemical reaction without chemically getting changed at the termination of the reaction. They never generate more product, they just generate the same concentration more briskly.  

A catalyst functions by providing an alternative pathway to lower the activation energy. This signifies that more of the collisions occurring will exhibit the essential activation energy. Thus, there will be more effective collisions per second.  

answer; i believe the answer is hydraulic action;