Question

How does temperature increase?

Answer 1

Increasing the temperature increases reaction rates because of the disproportionately increase in the number of high energy collisions.
It's only these collisions (possessing at least the activation energy for the reaction)
which results in a reaction!

Answer 2

Increasing the temperature increases reaction rates because of the disproportionately large increase in the number of high energy collisions. It is only these collisions (possessing at least the activation energy for the reaction) which result in a reaction.