The correct answer is option 2, isolation. Isolation is a mechanism that prevents interbreeding between different species or populations. It can occur in several ways such as geographic isolation, where physical barriers like mountains or bodies of water separate populations, or reproductive isolation, where individuals are unable to mate and produce offspring due to differences in behavior, mating rituals, or physical characteristics. Isolation is important for maintaining species integrity and promoting genetic diversity within populations. Adaptation, option 1, refers to the process by which species become better suited to their environment through inherited traits. Reproduction, option 3, refers to the biological process of producing offspring. Recombination, option 4, refers to the shuffling and recombination of genetic material during sexual reproduction.