Variation can be defined as the difference between the cells, organisms or group of organisms belonging to a particular species by environmental factors (phenotypic variation) or genetic differences (genotypic variations).
It is caused by gene mutations due to certain environmental factors and various combinations of genetic material.
Variation is important because it causes evolution and is the basis of heredity.
It is advantageous to a population as it enables few individuals to adapt to the environment changes thus, enabling the survival of the population.