Concept:The rate of change of a population depends mainly on factors that directly affect births and deaths, such as resources, enemies, and disease.
Explanation:Mutation is a change in an organism's genetic material or gene structure.
It may cause new traits to appear but usually does not immediately alter the number of individuals in a population.
Food supply, disease, and predation directly affect survival, reproduction, and death rates, so they strongly influence population number changes.
Mutation acts slowly through inheritance over several generations and is less direct.
Therefore, mutation has the least effect on the rate of change of the numbers in a population.
Answer:A. Mutation