Catalyst increases the rate of the reaction by

The catalyst can increase the rate of the reaction by binding to the enzyme and changing its conformation to favour substrate binding. The catalyst can also increase the rate of reaction by binding substrates and the reaction intermediates to it to increase the frequency of enzyme substrate collision to increase the rate of reaction. There are many ways that the catalyst can increase the rate of reaction, I have only listed two such possible ways

The offspring will be blood type aa, bb, ab and oo or i