In a population growth graph, a limiting factor typically determines the carrying capacity.

• A. A resource that increases the population size without bound.
• B. A factor that changes the genetics of individuals.
• C. A resource or condition that limits the size of a population.
• D. A method for measuring population density.

Answer: (C)

Carrying capacity is the maximum number of individuals an environment can support over time, given the available resources and conditions. A limiting factor is any resource or condition that prevents a population from growing beyond that limit. When resources like food, water, or space become scarce, or when factors like predation or disease increase, the population growth slows and eventually levels off around carrying capacity. That makes the statement describing a resource or condition that limits the size of a population the best fit. The other ideas don’t match: something that increases population without bound ignores the real limits of the environment; a factor that changes genetics points to evolution rather than immediate population regulation; and a method for measuring population density is just a way to count individuals, not a factor that limits growth.