Question

What is variation? Why is it seen in the offspring produced by sexual reproduction and not in the offspring produced by asexual reproduction?

Answer 1

Variation is the change in the genotype or phenotype of an org.

Sexual reproduction involves two DNA so more chances of variation are there....

Asexual rep. involves only one DNA..

Answer 2

The differences that occurs at the time reproduction and the off spring created is different from his parents is known as variation.

variation occurs  because the DNA copying from parents to the off springs is not exactly same.

It can be only  seen in sexual mode of reproduction because there are two different characters in sexual mode i.e. male and female and asexual mode have only one character.