A limiting factor is

• A. any factor that causes population growth
• B. a factor that exclusively affects predators
• C. the amount of resources available to an individual
• D. any factor that limits population growth

Answer: (D)

Limiting factors are factors that constrain how fast a population can grow or how large it can become. They can be resources like food, water, or space, or they can be threats such as predators, disease, or harsh weather. Because a limiting factor is defined by its effect—reducing population growth—the broad description that it is any factor that limits population growth best fits. This captures why growth slows or stops and why different situations (scarce resources, higher predation, or extreme conditions) can all cap how large a population can get. The other ideas are narrower or opposite in meaning: a factor that causes population growth would promote growth, which isn’t what limiting factors do, and focusing only on resources available to an individual misses the wider range of factors that can limit a population.