Answer:
Enzymes are affected by temperature. So, as temperature increases, enzymes activities also increases, till optimum temperature is reached. If it goes above the optimum temp, the enzymes becomes denatured or can't function anymore due to change in its active site.
As a result, when the temperature is cold, the enzymes doesn't have enough energy to collide and preform effectively because the number of successful collision between enzyme and substrate is reduced.
Enzymes works best at 37*C
