Carrying capacity is defined as

• A. The maximum population size that can be sustained indefinitely by the environment
• B. The average resources available per individual at carrying capacity
• C. The rate at which the population grows near carrying capacity
• D. The number of individuals added to a population each year

Answer: (A)

Carrying capacity is the maximum population size that the environment can sustain indefinitely given the available resources and conditions. This limit exists because finite resources like food, water, space, and habitat quality constrain birth and survival. As the population approaches this limit, competition intensifies, causing the growth rate to slow until births balance deaths and the population level stabilizes around that size. It’s about how many individuals can be supported over time, not how fast the population is growing at any moment. The idea in the other options—resources per individual, the growth rate near the limit, or the annual increase—are related concepts, but they describe different aspects, not the defining size limit.