What is the primary benefit of having hybrid vigour in offspring?

The primary benefit of having hybrid vigour in offspring is higher evolutionary fitness. Hybrid vigour, also known as heterosis, refers to the phenomenon where hybrid offspring exhibit enhanced biological qualities compared to their parents. This often includes increased growth rates, improved resistance to disease, and greater reproductive success, all of which contribute to the overall fitness of the individuals in a population.

Higher evolutionary fitness is advantageous because it enables these hybrids to thrive in various environments, potentially leading to better survival rates and greater adaptability. When hybrids outperform their parent strains, it can result in a more resilient population that is better equipped to face challenges such as changing environmental conditions or competition for resources.

In contrast, the other options highlight aspects that are not beneficial in this context. For example, increased likelihood of inbreeding would generally lead to decreased fitness due to the accumulation of deleterious alleles. Lower genetic diversity is detrimental as it reduces a population's ability to adapt to environmental changes, and weakness against environmental changes represents a lack of resilience that hybrid vigour actively combats. Thus, the enhancement of evolutionary fitness through hybrid vigour is pivotal for the long-term success of a species.