Question

question 11
bone marrow produces
vitamin d
calcium
red blood cell
keratin

Explanation:

Bone marrow is a soft tissue found inside bones. It is responsible for hematopoiesis, the process of producing blood cells. Red blood cells (erythrocytes) are produced in the red bone marrow. Vitamin D is synthesized in the skin (with the help of sunlight) and also obtained from diet. Calcium is mainly obtained from the diet and is stored in bones. Keratin is a protein produced by epidermal cells in the skin, hair, and nails.

Answer:

red blood cell