Answer:
A. synthesis of vitamin C.
Explanation:
Integumentary system refers to the skin and its appendages. So it doesn't have the role to synthesis vitamin C, but it can synthesis vitamin D through exposure to UV light. The major role of integumentary system is protective role (immuno defense-from infections, dehydration, temperature changes, protection of underlying tissue etc). It also contains many receptors (for pain, touch, temperature change) that detect environmental changes.
Answer: fat......................................
