Which statement is true about a population at carrying capacity?

• A. The growth rate is zero
• B. The population continues to increase
• C. Birth rate far exceeds death rate
• D. Resource availability increases

Answer: (A)

Carrying capacity is the maximum number of individuals the environment can support indefinitely with finite resources. When a population reaches this size, the growth rate is zero because births balance deaths, so there is no net change in population. In the logistic growth model, dN/dt = rN(1 − N/K); at N = K, the growth term becomes zero, so the population stops increasing. Resources aren’t increasing at this point; they’re just sufficient to support that steady number, and competition is high. Birth rates do not vastly exceed death rates here—they’re balanced, yielding zero net growth. If resources increased and carrying capacity rose, the population could grow again, but at carrying capacity the key fact is zero growth.