Here's why:

* Sexual reproduction introduces variation: Sexual reproduction involves the combination of genetic material from two parents. This mixing of genes leads to offspring with unique combinations of traits, creating variation within the population.

* Importance of variation: Variation is crucial for a species' survival. It allows populations to adapt to changing environments, resist diseases, and evolve over time.

Let me know if you'd like more details on the mechanisms of sexual reproduction and how they contribute to genetic variation!