While You Develop Calloused Feet When You Go Barefoot for a Summer,your

Multiple Choice

While you develop calloused feet when you go barefoot for a summer,your neighbor remains a tenderfoot by protecting her feet with shoes.The differences in skin toughness between you and your neighbor are best attributed to

A) the molecular structure of genes.
B) person-to-person genetic variations.
C) the impact of epigenetic marks on gene expression.
D) the interaction of genetic and environmental influences.