The answer is DNA (Deoxyribonucleic acid).
DNA is the molecule present in the nucleus of our cells that has all of our genetic instructions. This molecule consists of a double-helix ribbon composed of nucleotides that will dictate most of our traits. I say 'most' because some traits result from an interaction with the environment.
During sexual reproduction, DNA from our parents is inherited to us. That's why we have physical similarities and also in personality to our parents.
