Answer:
Natural selection
Step-by-step explanation:
Natural selection favors the individuals carrying the adaptive variations and allows them to reproduce more as their beneficial variations impart them the survival advantage. These individuals with beneficial adaptive traits reproduce more and produce a large number of progeny, all carrying the useful adaptive features of the parents.
Hence, natural selection favors individuals with beneficial variations. The differential rate of reproduction of the favored individuals allows inheritance of favored variations to the future generations.