Final answer:
Sexual reproduction creates genetic diversity which benefits species survival in changing environments, despite potential disadvantages such as needing two different sexes and possibly fewer offspring compared to asexual reproduction.
Step-by-step explanation:
Sexual reproduction is useful because it results in genetic diversity. When two cells combine during sexual reproduction, they each contribute different sets of genes, leading to offspring that differ genetically from their parents. This variation in traits can be beneficial for the survival of the species, especially in changing environments, where different characteristics might be advantageous for survival and reproduction. Sexual reproduction also entails the maintenance of two separate sexes within a species, which can be seen as a disadvantage because only one sex (typically females) produces offspring, potentially resulting in fewer offspring in total than asexual reproduction would allow. However, despite the potential for fewer offspring and the need for two different sexes, the advantage of producing genetically varied offspring is considered significant in the long-term resilience of a species.