Explain the concept of nutrient limitation and its effect on population growth.

• A. Limited nutrients restrict growth; leads to carrying capacity plateau.
• B. Nutrients always increase growth without limit.
• C. Nutrient abundance decreases carrying capacity.
• D. Nutrient limitation speeds up population growth rate indefinitely.

Answer: (A)

Nutrient limitation means essential resources like nitrogen or phosphorus are scarce, so organisms can’t harvest energy and build biomass as efficiently. When nutrients are limited, the per-capita growth rate drops, births may slow or deaths may rise, and the population grows more slowly until it levels off at a carrying capacity—the maximum population the environment can sustain with the available resources. If nutrients were plentiful, carrying capacity could be higher and growth could proceed further, but with limited nutrients the environment imposes a ceiling. The other statements misstate what happens: unlimited growth isn’t possible when resources are finite, abundance doesn’t inherently reduce carrying capacity, and limitation does not cause growth to speed up indefinitely.