Which of the following is NOT a primary function of the skin?

• A. Synthesis of vitamin D
• B. Production of red blood cells
• C. Regulation of body temperature
• D. Protection against pathogens

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by identifying the primary functions of the skin. The skin is the largest organ of the body and plays several critical roles, including protection, regulation of body temperature, and synthesis of vitamin D.
2. Step 2: Understand the synthesis of vitamin D. The skin contains cells that produce vitamin D when exposed to ultraviolet (UV) light from the sun. This is a well-documented function of the skin.
3. Step 3: Examine the regulation of body temperature. The skin helps regulate body temperature through mechanisms such as sweating and vasodilation (widening of blood vessels) or vasoconstriction (narrowing of blood vessels). This is another primary function of the skin.
4. Step 4: Consider the protection against pathogens. The skin acts as a physical barrier, preventing harmful microorganisms from entering the body. It also contains immune cells that help fight infections, making this a key function of the skin.
5. Step 5: Evaluate the production of red blood cells. Red blood cells are produced in the bone marrow, not the skin. Therefore, this is NOT a primary function of the skin, making it the correct answer to the question.