number because a normal karyotype has 22 autosomes and 1 pair of s€x chromosomes
(sorry if I'm wrong)
Structurally, DNA and RNA are nearly identical. As mentioned earlier, however, there are three fundamental differences that account for the very different functions of the two molecules. RNA has a ribose sugar instead of a deoxyribose sugar like DNA. RNA nucleotides have a uracil base instead of thymine.