Step-by-step explanation:
According to Darwinism , the survival of the fittest , variation is important because it allows species to adapt to its environment , the stronger in traits is selected and the weakest is unable to adapt and die.
so , variation is the only way for a species to acquire new traits that can enable them to survive and adapt to their surroundings, Normally , Variation is very slow and it requires many generations for new traits to emerge , but it happens.