What is variation?

Hint: The method which is evolved in order to create slight changes in an organism to make it sustain in the environment that changes and also to develop new species from older ones which are better in adaptability like humans are the result of variations in monkeys.

Complete answer:
Variation is the scientific term used for changes in genetic makeup of a cell. It can be caused by natural selection, genetic drift, mutation, recombination or change in allele during sexual reproduction. Variations may also occur due to environmental factors like extreme heat, UV radiations, exposure to chemical substances, etc.

Additional Information: -Genetic variation can be identified at many levels. It is possible to identify genetic variation from observations of phenotypic variation in either quantitative traits e.g., leg length in dogs or discrete traits e.g., white, pink, red petal colour in certain flowers.
-The variation in the genetic material can vary in size i.e. it can also be a few base pairs long or thousands of base pairs long.
-Based on location or function of cell, the variation can be of two types: germinal variation and somatic variation.
-Germinal variations are found in germinal cells or gametes and are inheritable.
-Somatic variation is found in all other cells and cannot be inherited.

Note: Genetic variations play an important role in evolution as they help in deletion of unhelpful characteristics as well as make positive changes in an organism helping them evolve. Accumulation of variations over a period of time thus leads to speciation.