Vitamins have many functions throughout the body. for example, vitamin d function as antioxidants, the function as coenzymes, and is important for calcium regulation.

(a) true
(b) false

(A) True

Explanation:

Vitamins are important for the human body because it plays an important function in the body like in metabolism, calcium absorption, releasing energy from food, cell damage repair, etc.  

For example, vitamin D can be made by the body itself. This vitamin is made by the skin when UV radiation from the sun falls on the skin. This vitamin act as membrane antioxidant and helps in inhibiting iron-dependent lipid peroxidation in cell's liposomes.

It also helps in calcium regulation in the body and without vitamin D the dietary calcium is not properly absorbed.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.