Which statement correctly defines carrying capacity?

• A. The fastest possible population growth rate.
• B. The amount of energy available in the ecosystem.
• C. The maximum population size the environment can sustain indefinitely.
• D. The number of species in an area.

Answer: (C)

Carrying capacity is the maximum number of individuals of a species that an environment can support indefinitely given the available resources like food, water, space, and other factors. As a population grows and resources become more limited, the growth rate slows and tends to level off; births balance deaths and the population stabilizes at this limit. If the population overshoots, resources run short and the numbers decline again until balance is restored. The correct statement captures this idea of a sustainable maximum size. The other options describe different ideas—how fast a population grows, the total energy in the ecosystem, or how many species are present—not the long-term limit on how many individuals a habitat can support.