Which statement about carrying capacity is true or most accurately reflects its meaning?

• A. It is the minimum population size required for persistence
• B. It is the average population size over time
• C. It is the maximum population size the environment can sustain indefinitely
• D. It is the total number of individuals that have ever lived in the population

Answer: (D)

Carrying capacity is the maximum number of individuals a population that the environment can sustain indefinitely, given the available resources, space, and ecological interactions. As a population grows, resources become limiting, competition increases, and the growth rate slows until births roughly balance deaths, keeping the population around that limit. This capacity can change if conditions shift, such as changes in resource availability or climate. The other ideas describe different concepts: a minimum viable population relates to long-term persistence and genetic viability, an average over time is just a mean value, and the total number ever lived is a cumulative count, not a sustainability boundary.