The main function of vitamin d is to promotea.
a. calcium and phosphorus absorption, and calcium mobilization from bone.
b. synthesis of carotenoids and controls absorption of fat-soluble vitamins.
c. conversion of calcium and phosphorus to more readily absorbable compounds.
d. secretion of calcitonin. e. synthesis of dehydrocholesterol.

a. calcium and phosphorus absorption, and calcium mobilization from bone.

Explanation:

Vitamin D is a fat soluble vitamin. It is present in very few foods and also synthesized when skin is exposed to sun's ultra violet rays. In humans, the most important forms of Vitamin D are D3 and D2.

It plays an important role in maintaining the required level of calcium and phosphorus in blood by many ways:

alternate days of the week that you perform that activity