Concept:Density-dependent factors strengthen as population size increases, whereas density-independent factors affect a population regardless of its size.
Explanation:Buildup of waste products, predation, and parasitism all become more intense when the mouse population grows larger, so they are density-dependent factors.
Unfavourable climate, however, affects the mice equally whether the population is small or large, making it a density-independent factor.
Therefore, unfavourable climate is the factor least likely to act as a density-dependent limiting factor.
Answer:D. Unfavourable climate