Which scenario best illustrates a density-independent factor limiting human population growth?

Which scenario best illustrates a density-independent factor limiting human population growth?

• A. A severe drought reduces food supply regardless of population size
• B. A water shortage due to overuse from a large city
• C. A local outbreak spreads through crowded neighborhoods
• D. Competition for resources intensifies as population grows

Answer: (A)

Density-independent factors are environmental conditions that affect a population regardless of its size. A severe drought reduces food supply regardless of how many people are in the area, so its impact does not scale with population density—it’s driven by climate, not by the number of individuals. The other scenarios show density-dependent effects: a water shortage from overuse by a large city depends on how many people are consuming water; outbreaks in crowded neighborhoods spread more easily where contact rates are higher; and competition for resources grows as more individuals vie for the same limited supplies.

Density-independent factors are environmental conditions that affect a population regardless of its size. A severe drought reduces food supply regardless of how many people are in the area, so its impact does not scale with population density—it’s driven by climate, not by the number of individuals. The other scenarios show density-dependent effects: a water shortage from overuse by a large city depends on how many people are consuming water; outbreaks in crowded neighborhoods spread more easily where contact rates are higher; and competition for resources grows as more individuals vie for the same limited supplies.