Answer:
Chromosome structure consists of a long arm region and a short arm region connected at a central region known as a centromere. The ends of a chromosome are called telomeres. Duplicated or replicated chromosomes have the familiar X-shape and are composed of identical sister chromatids.
Explanation:
Electron shell is the outer orbital, while the inner orbital are just called orbitals.
Carbohydrates
lipids
amino acid
nucleic acid ?