What is an example of a density-dependent factor?

Density-dependent factors are those that have an increased effect as the population density increases. They typically involve interactions among individuals within a population that can affect growth rates and mortality rates. Competition is a prime example of a density-dependent factor because, as a population grows larger, individuals compete more intensely for limited resources such as food, shelter, and mates. This competition can lead to increased stress, decreased reproduction rates, and higher mortality rates when resources become scarce.

In contrast, natural disasters and unusual weather are examples of density-independent factors. These factors impact populations regardless of their size and density, often causing sudden changes that can affect populations but do not depend on population density. Habitat destruction can be influenced by human activity and can affect populations both in large and small densities, but it does not inherently change based on the population size itself. Therefore, competition is the correct choice as a density-dependent factor.