Variation 

Variation is defined as the small changes or differences among the members of a species which happens over the period of time .

• During the process of reproduction there is always a chance of variation. This is necessary for the evolution of organisms. 
• It can be changed in the traits like color of hair or eyes which the offspring exhibits.
• Variation is responsible for the different morphological and physiological features in organisms. 

Importance of variation 

• Variations increase the chances of survival of organisms in a changing environment. 
• It makes organisms better fitted for the struggle of existence.
• It forms the basis for evolution
• It produces different gene combinations which result in new offspring to become more immune to other diseases.