What causes a population to increase and decrease ?

Aboy jumps into a cold swimming pool and his body tempature goes down hus muscles ,blood vessels

Migration is a. the movement of organisms from a native location to a foreign location b. the movement of organisms from a foreign location to a native location the movement of organisms from their water supply to their food supply d. the seasonal movement of organisms between locations c. select the best answer from above

This is the nitrogenous base only found in rna