While you develop callused 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

Option-D

Explanation:

The skin toughness trait is determined by the genes which can control the components of skin like the amount of the collagen and the elastin.  Also, the trait is influenced by the environmental factors which can act as a stimulus to either increase or decrease the components of the skin.

In the given case, when you walk barefooted develops the callus but when you walk with the shoes you do not develop calluses. Here the development of calluses is influenced by the environment which can lead to the increased production of collagen genetically which provides strength.

Thus, Option-D is the correct answer.

d. groundwater flows through the subsoil and deposits minerals.