Answer:
A catalyst works by providing a different pathway for the reaction, one that has a lower activation energy than the uncatalyzed pathway. This lower activation energy means that a larger fraction of collisions are successful at a given temperature, leading to an increased reaction rate.
Explanation:
Khan Academy is a great homework site:
https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:kinetics/x2eef969c74e0d802:catalysis/v/catalysts
you can also use this video:
https://youtu.be/if5JGssffm8