Question

question :
If N2O4 gas is placed in a sealed vessel the following equilibrium is established.
N2O4(g) -> 2NO2(g)
The forward reaction is endothermic.
What happens when the temperature is increased?
1 The equilibrium constant increases.
2 The partial pressure of NO2 increases.
3 The activation energy is unchanged.

answer is 1,2,3 all correct, but why activation remain unchanged when temperature increases ? and explain th partial pressure of NO2 increases pls ! :)