How does a catalyst work?
a) it shifts the reaction toward the products
b) it changes the pressure of the products
c) it increases the temperature of reactants
d) it increases the temperature of the products
e) it decreases the activation energy hurdle

A catalyst decreases the activation energy hurdle. It provides an alternate pathway to the reaction product by decreasing the activation energy hurdle. The rate of the reaction increases as now the activation energy decreases. A catalyst alters the reaction rate without being consumed in the reaction.

d.) circle motion requires a force to give it a centripetal acceleration.