DNA is exactly the same in every species it is found in. It always has a sugar-phosphate backbone and the same four bases - A, T, G and C. The only thing that changes is the number of genes found in...
because they do
A human ;) But the human DNA is developed from the zygote, so when the sperm fertilizes the egg in the womb.
Yes, all animals and plants have DNA
The skin of the human being is like a waterproof envelope that keeps the body's insides & water in, and the dryness of the air & infections out.