Contributing to cell membrane function, making bile acids essential for fat absorption, metabolizing fat-soluble vitamins, and making vitamin d are all functions of which nutrient? (a) protein.(b) carbohydrate.(c) cholesterol.(d) omega-3 fatty acids.

C. Cholesterol

Explanation:

Cholesterol maintains the fluidity of the cell membrane and thereby, regulates its function.

Bile acids are derived from cholesterol which serves as their precursor. For example, Taurocholic acid is a polar derivative of cholesterol. Bile acids serve in the absorption of fatty acids, glycerol, and fat-soluble vitamins as these compounds are non-polar in nature.  

Vitamin D is produced when the derivative of cholesterol, 7-dehydrocholesterol undergoes photolysis in skin cells in presence of sunlight.  

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.