Which of the following plasma proteins is responsible for colloid osmotic pressure?

a. Presence of calcium: Calcium does not directly stimulate the production of Vitamin D in the skin.

b. Exposure to ultraviolet light: UVB rays from sunlight stimulate the skin to produce Vitamin D3 (cholecalciferol).

c. Exposure to cold temperature: Cold temperature does not affect Vitamin D production.

d. Presence of parathyroid hormone: Parathyroid hormone helps regulate calcium levels and can stimulate the conversion of Vitamin D to its active form in the kidneys, but it does not stimulate its production in the skin.

a. Forming the contractile component of the digestive, urinary, and reproductive systems: This describes smooth muscle, not skeletal muscle.

b. Contracting to cause involuntary muscle movements: This is a characteristic of smooth and cardiac muscles. Skeletal muscle is primarily involved in voluntary movements.

c. Pumping blood throughout the body: This is the function of cardiac muscle, not skeletal muscle.

d. Shivering for heat production: Correct. Skeletal muscles generate heat through shivering, which is an involuntary contraction response to cold.