Which term describes a constant population size despite changes in births and deaths, often due to limits from resources?

• A. Birth rate
• B. Death rate
• C. Carrying capacity
• D. Plateau

Answer: (D)

Carrying capacity explains why a population can stay at roughly the same size over time even as births and deaths continue. It’s the environment’s maximum number of individuals it can sustain indefinitely with available resources. When a population reaches this limit, resources become limiting, and the rate at which new individuals are born tends to balance the rate at which individuals die. The result is a stable, constant population size—the equilibrium at the carrying capacity. A plateau describes the observed leveling-off on a graph, but carrying capacity is the term that identifies the underlying limit causing that pattern.