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

question 63

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.

---

Definitions:

Economic Profits

The difference between the total revenue earned by a business and the total costs (both explicit and implicit) of all inputs used, representing the additional gain over and above the opportunity costs.

Accounting Profits

The difference between total revenue and explicit costs; essentially the bottom line of a company's income statement.

Perfectly Competitive

A market structure characterized by a large number of small firms, homogenous products, and free entry and exit, where no single firm has market power.

Variable Cost

Expenses that fluctuate with the level of output or business operations, contrasting with fixed costs.