Do all your pet's offspring look the same? if no, then explain why they look different.

All your pet's offspring will not look exactly the same due to the second step in natural selection; variation. Each offspring will look similar due to common ancestry, but they each have their own genetic code (DNA). Mutations in the DNA can account for these anatomical differences. When the coding of DNA is copied, there are three possible things that can happen: deletion, substitution, and frame shifts which all account for physiological and anatomical differences between the animal's offspring.

The basic building blocks of dna and rna are nucleotides