CBSE Class 10 Answered

DNA present in chromosomes of cell nucleus determines the body design of an individual.  They contain information for inheritance of features from parents to next generation. They are passed down from parents to offspring to perpetuate life. The joining of an egg and sperm during reproduction produces the zygote which contains the complete genetic code that our body uses for life. Here half of the DNA comes from father and half from mother.

A basic event in reproduction is the creation of a DNA copy. The process of DNA copying will have some variations each time due to which the surviving cells are similar to, but subtly different from each other. This inbuilt tendency for variation during reproduction is the basis for evolution.

Thus DNA copying plays an important role in inheritance of characters from parents to offspring as well as in proper survival of organism by similar copying.