The change in the single base pair of the DNA can lead to mutation. The change in the base pair changes the proteins coded by the triplets.
It is not necessary that every mutation is harmful it may be beneficial for the organisms.
The mutation in the body can be very much useful for the organism as it can lead to diversity which increases the chances of survival.
Incase there is a unusual situation which is not normal then the mutated organism might have higher chances of survival which is due to diversity of organism.
