Final answer:
Predation is a limiting factor that keeps populations from growing.
Step-by-step explanation:
A limiting factor that keeps populations from growing is predation. Predation is when one organism, known as the predator, hunts and kills another organism, known as the prey. As the prey population decreases, the predator population begins to decrease as well. This predator-prey relationship acts as a limiting factor on population growth for both species.