Answer:
Option-A
Explanation:
Vitamin D is an essential nutrient required by the body to maintain its structure as vitamin D helps in the absorption of the calcium and phosphorus which are required in maintaining the bones.
The biosynthesis of vitamin D begins in the skin when the cholesterol, a precursor of the vitamin D gets activated by the Ultraviolet B of the sunlight. When the UV B touch the skin, they convert the precursor to vitamin D3. The vitamin D3 gets transported to the kidney and liver where the enzymatic action converts the vitamin D3 to the active form of vitamin called calcitriol.
Thus, Option-A is the correct answer.
Arteries<span> have thick, elastic, muscular walls whereas </span>veins<span> have thin walls with few elastic fibers</span>
No but the most overconsumed are salty overly processed goods?
<span>Hydrogen is the answer</span>
