B-complex is an often prescribed vitamin. What is complex about it and what is its usefulness?

Explanation

A group of vitamins containing vitamin `B_1`, `B_2`, `B_6`, `B_(12)` , biotin, pantothenic acid, folic acid and nicotinic acid is called vitamin B-complex. It is so named because it is not a single vitamin but is a group of vitamins. It is required to release energy from food and to promote healthy skin and muscles. Its deficiency causes diseases like beriberi (vitamin `B_1`) and pernicious anaemia (Vitamin `B_(12)` )