Solution

Heterosis is often attributed to a combination of factors, including dominance, overdominance, and sometimes epistasis. Dominance and overdominance are particularly important contributors to the increased vigor and performance observed in hybrid offspring. The combination of favorable alleles from both parents can result in improved traits compared to either parent. Epistasis, or gene interaction, may also play a role in some cases, where the effect of one gene depends on the presence of alleles at another gene. Overall, heterosis is a complex phenomenon influenced by various genetic mechanisms.