The gravity from the moon and some from the sun brings the tides up, because the moon's gravitational force is strong enough to pull some water up.
It is only active at a pH of around 2 because that is around the same pH as the gastric juices in the stomach which is where pepsin is used to break down proteins.
C. the flies could not get into the jar to lay their eggs
Actually the answer is none of the answers
They are all transfer of heat in many ways
The answer is CrossBreeding