$\begin{array}{1 1} \text{a.Under certain circumstances, heterozygotes are superior to either possible homozygotes} \\\text{b.Disease causing homozygous recessive phenotypes from either parents are masked} \\\text{c.Offspring from a hybrid cross usully possessthe best of two desirable parents} \\\text{d.Inherently, hybrids have no deleterious mutations} \end{array} $
