Which of the following acts as a promoter for nickel in the hydrogenation of oils?

In case of autocatalysis,

In a chemical reaction,a catalyst . . . . .

$A$ catalyst is used:

What is a catalyst?

Which reaction characteristics are changing by the addition of a catalyst to a reaction at constant temperature: $(i)$ Activation energy,$(ii)$ Equilibrium constant,$(iii)$ Reaction entropy,$(iv)$ Reaction enthalpy?