Darwin's theory suggested that nature selects those individuals who are best adapted to the environment to survive. What is this mechanism commonly called?

• A. Natural selection
• B. Genetic drift
• C. Mutation
• D. Migration

Answer: (A)

Natural selection is the mechanism at work here: advantageous traits become more common in a population because individuals with those traits are more likely to survive and reproduce in the given environment. When there’s variation among individuals, the environment acts as a filter, favoring those traits that enhance survival or reproductive success. Over many generations, this differential survival and reproduction shifts allele frequencies, leading to adaptation to the environment.

This isn't a random process—it's driven by how well traits fit the current conditions. In contrast, genetic drift involves random changes in trait frequencies that can occur by chance, especially in small populations. Mutation is the source of new genetic variation, not the selective process itself. Migration (gene flow) changes frequencies by moving genes between populations, not by differential survival.