The maximum size of a population that the environment can support.

• A. Carrying capacity
• B. Biotic potential
• C. Maximum sustainable population
• D. Growth rate

Answer: (A)

Carrying capacity is the largest number of individuals of a species that an environment can support indefinitely given the available resources like food, water, space, and shelter. When a population grows toward this limit, resources become scarcer and the balance shifts so that births and immigration slow down or deaths and emigration increase, causing the growth to level off. If the population exceeds this limit, resource shortages lead to higher mortality or lower reproduction until the size drops back toward the carrying capacity. This concept captures how ecosystems constrain population size in the real world, beyond just how fast a species could reproduce.

Biotic potential refers to the maximum possible growth rate under ideal conditions, not the sustainable limit in a real environment. Growth rate describes how quickly the population changes over time, not the maximum size it can reach. The term “maximum sustainable population” isn’t the standard ecological term used for this limit.