DNA is composed of long strings of nucleic acid sequences, but not all of them code for proteins.But the ones that do are called genes.
Alleles are different versions of a certain gene.As an example, the gene that codes for blood type has 3 different alleles, A, B, an O. The genes that code for hair and eye color also have many different alleles.
The answer is A because D is the most recent layer so it would go D,C,B,A
Provides support and energy
A particle that has 14 protons, 14 neutrons, and 14 electrons