The four main categories of biomolecules are carbohydrates, lipids, proteins and nucleic acids. While there are some special cases to be found, these four molecules make up the bulk of living bodies, and each plays an essential role in regulating the body's chemistry.
This can happen because you have recessive and dominant characteristics passed down. So you can get a totally different chromosome that doesn't come from your parents because your grandparents may have had it or great grand parents, the line keeps going .
