In a population at carrying capacity, what role do limiting factors play?

• A. They prevent any change.
• B. They keep population size near the carrying capacity by limiting resources.
• C. They increase resources.
• D. They erase density.

Answer: (B)

Limiting factors regulate how big a population can get when resources are finite. When a population sits at carrying capacity, the environment can support only a certain number of individuals with the available food, space, and other resources. As numbers approach that limit, competition increases and birth rates may drop while death rates rise or individuals leave the area. These pressures prevent the population from growing beyond what the environment can sustain, so the size tends to hover around the carrying capacity rather than continuing to rise. This is a matter of density-dependent regulation: the larger the population, the stronger the limiting effects become, keeping the population near the carrying capacity. Limiting factors don’t create resources or erase density; they act to balance growth with resource availability.