Question

The source of retinol (vitamin A):
(A) Liver
(B)Kidney
(C) Fish oil
(D) all of the above

Answer 1

Vitamins are related to biomolecules. Biomolecules are lifeless compounds which are very essential for the growth and development of the bodies of living things. Living things include plants and animals.

Complete answer:
Vitamins are the organic compounds which are necessary for well-functioning of the body but if deficiency of vitamins occurs in living things that cause specific disease.
Most of the vitamins in human beings cannot be synthesised in the body but in plants and animals mostly synthesis all of them.
Vitamin A also known as retinol and is very useful for eyesight. The molecular formula of Vitamin A $C{}_{20}^{}{H_{30}}O$. And the molecular mass of Vitamin A is $286.45g/mol$. Two types of vitamins on the basis of their source-$\left( 1 \right)$ Animal vitamins- If vitamins are produced by animals like Vitamin A is found in animal products like meat, fish.
$\left( 2 \right)$ Plants vitamins- If vitamins are produced by plants like Vitamin A is found in plant products like Fruits and vegetables (carrot).

Hence, option D is the correct option. The source of vitamin A is liver, kidney, fish oil.
Note:
Vitamins are two types on the basis of their solubility-
Fat soluble vitamins- These are the vitamins which are soluble in fat and oil but are insoluble in water. Examples of fat soluble vitamins are Vitamin A, vitamin D, vitamin E,Vitamin K.
Water soluble vitamins- These are vitamins which are soluble in water. Examples of water soluble vitamins are- Vitamin B complex like vitamin${B_{12}}$.
Fat soluble vitamins are stored in the liver and adipose tissue in human beings.