Mastering Biology Practice Test

Carrying capacity is the environment’s long-term limit on how many individuals it can sustain, based on available resources, habitat conditions, and ecological pressures. The idea that this limit can change comes from factors that alter those resources or conditions. Resource availability directly sets how much food, water, and shelter are possible, so more resources raise the potential carrying capacity and depletions lower it. Climate shapes the overall habitat quality and resource fluctuations, so a wetter year or a harsher season can increase or decrease how many individuals the area can support. Predation pressure changes how many individuals can survive given those resources, effectively adjusting the sustainable population size down if predators keep removing individuals.

The option describing the maximum number of individuals in a population is simply a description of carrying capacity itself, not a driver that changes it. It’s the outcome, not a factor that alters how large the population can be.