What are some of the biological features that humans have developed that the early mammals did not possess?

Your Inner Reptile" traces our hair, skin, teeth, jaws and sense of hearing back to reptilian ancestors — from ferocious beasts that ruled the Earth to a little shrew-like animal that lived 195 million years ago.

chromosomes carry the genetic information for organisms. also, chromatin is the thread like dna which is located in the nucleus of an organism.

your answer is rna to the question.