Answer:
Natural selection drives evolution by preserving favorable variations and causing the extinction of unfavorable variations.
Step-by-step explanation:
Natural selection is the process by which forms of life having traits that better enable them to adapt to specific environmental pressures, as predators, changes in climate, or competition for food or mates, will tend to survive and reproduce in greater numbers than other of their kind, thus ensuring the perpetuation of those favorable traits in succeeding generations. Evolution is the change of a gene pool of a population from generation to generation by such processes as mutation, natural selection, or genetic drift.