How do temperature and the presence of a catalyst bring about an increase in the rate of a reaction ?

A catalyst increases the rate of a reaction by:

A catalyst increases the rate of a chemical reaction by

Catalyst increases the rate by

Which meristem bring about increase in the girth of trees?

In the presence of a catalyst, the heat evolved or absorbed during the reaction:

In the presence of a catalyst, the heat evolved or absorbed during the reaction:

Given : AhArrB+C, DeltaH=-"10 kcals" , the energy of activation of backward reaction is "15 kcal mol"^(-1) . If the energy of activation of forward reaction in the presence of a catalyst is "3 kcal mol"^(-1) the catalyst will increase the rate of reaction at 300 K by the number of times equal to