Which term describes an environmental constraint that slows or stops population growth?

• A. Tides
• B. Carbon cycle
• C. Limiting factor
• D. Organ system

Answer: (C)

A limiting factor is an environmental constraint that slows or stops population growth. In ecosystems, a population tends to grow when resources are plentiful, but as numbers rise, factors such as limited food, water, shelter, or space, as well as disease or predation, begin to constrain further growth. These factors determine the carrying capacity of an environment—the largest population size that can be sustained indefinitely. When limiting factors kick in, growth shifts from rapid (exponential) to leveling off (logistic growth) as the population approaches that carrying capacity. Tides describe ocean level changes, the carbon cycle explains how carbon moves through Earth’s systems, and organ systems are parts of the body; none of these describe the environmental constraint that directly slows or stops population growth.