6) D

1 – When temperature increases, molecules gain more kinetic energy, therefore they move around a lot. This increases the probability of more collisions with surrounding molecules per unit time. So 1 is correct.

2 – Since the molecules gain more kinetic energy, the probability of collisions with more activation energy will also increase. So 2 is correct.

3 – An increase in kinetic energy does not alter the orientation of molecules. So, 3 is wrong.