Which process results in the evolution of organisms best adapted to the environment through differential reproduction?

• A. Gene therapy
• B. Adaptation
• C. Natural selection
• D. Divergent evolution

Answer: (C)

Differential reproductive success shaping a population over generations is natural selection. In any population with heritable variation, individuals whose traits improve survival or mating success leave more offspring. Those advantageous traits become more common in the next generation, and after many generations the population becomes better adapted to its environment. This mechanism explains how evolution occurs through environmental pressures selecting for traits that increase fitness.

Medical gene therapies introduce genes for treatment, rather than driving evolutionary change in a population. Adaptation is a broad term for becoming better suited to conditions, but natural selection is the process that explains how such suited traits spread via differential reproduction. Divergent evolution describes the splitting of lineages into different species due to evolving differences, not the ongoing differential reproduction within a single population.