A limiting factor whose effect increases with population size is called a density dependent factor.

• A. Density independent factor
• B. Carrying capacity
• C. Density dependent factor
• D. Reproductive rate

Answer: (C)

Density-dependent factors are factors whose impact grows as the number of individuals increases. When a population becomes crowded, resources like food and water become scarcer, competition intensifies, and diseases spread more easily, all of which raise mortality or lower birth rates and slow growth. This is why such factors help regulate populations toward the environment’s carrying capacity, the maximum sustainable size given resources and space. In contrast, density-independent factors affect populations regardless of how many individuals are present—events like floods or droughts can reduce numbers no matter the density. Carrying capacity is the level at which the environment can sustain the population, not a factor whose effect changes with density. Reproductive rate describes how many offspring individuals tend to have, not how the impact of a factor changes with population size.