Given a scientific question, generate a correct answer to it.

[EX Q]: Overpopulation takes place when the number of organisms in an area exceeds what?
[EX A]: carrying capacity

[EX Q]: Where do birds store and moisten food that is waiting to be digested?
[EX A]: crop

[EX Q]: What is the series of changes in the life of an organism?
[EX A]:
life cycle