Answer:
Predation and disease
Explanation:
Population growth is limited by density-dependent factors such as predation and disease.
Predation is exercised by secondary, tertiary or top-of-the-food chain consumers. In a long study of tundra mice, researchers observed that the fluctuations in population density that occurred over time were entirely dependent on the predation exerted by owls and snow foxes. As the rat population grew to very high densities, the predation rate increased, limiting the uncontrolled growth of these rodents. This caused an increase in the ferret population, the main competitors of mice. With the reduction in the rat population, predators were preferably hunting ferrets, removing predation pressure under the rapidly growing rat population.
Disease, in turn, is another limiting factor as it causes the death of many individuals in a population, causing a decrease in the size of that population. Similarly, as the disease is wiped out, the size of the population begins to grow again.
