Nitrogen,<span>The atmosphere is composed of ~78% nitrogen and ~21% oxygen, with small amounts of other gases. The bulk composition of the earth by weight is mostly, iron, oxygen, silicon and magnesium, in that order, with all the other elements making up only about 5% of the earth's weight.</span>
The element found in both DNA and protein is nitrogen
The genotype<span> is the set of genes in our DNA which is responsible for a particular trait. The </span>phenotype<span> is the physical expression, or characteristics, of that trait. I'm just defining them but I hope it helps you </span>