Which of the following is an example of density dependent limiting factors?

• A. Earthquake
• B. Weather
• C. Seasonal migration
• D. Disease

Answer: (D)

Density-dependent limiting factors are those whose impact on a population grows as population size increases. Disease is the classic example because when individuals live closer together or interact more, pathogens spread more easily, leading to higher illness rates and greater effects on survival and reproduction as density rises. In contrast, earthquakes and weather affect populations regardless of how many individuals are present, so their impact isn’t tied to density. Seasonal migration is a behavioral response to resources rather than a factor that scales with population size. So disease best illustrates a factor whose influence strengthens with crowding.