“Genes and environmental effects are often part of the explanation. “
“...disease-causing alleles of one gene may be suppressed by alleles of another gene elsewhere in the genome, or a person's overall health may influence the strength of a disease phenotype.”
https://www.khanacademy.org/science/high-school-biology/hs-classical-genetics/hs-non-mendelian-inheritance/a/polygenic-inheritance-and-environmental-effects
(D) It is caused by rhinovirus.
Cultivated crops usually have fewer roots such as corn in a moist or wet soil. <span>To have more hair roots needs more air and oxygen helps to make it happen. </span><span>But a wet soil doesn't help add more roots. </span>
<span>C.
has strong legs for running
</span>
