Answer:
Nitrogen about 77 percent of the atmosphere is composed of nitrogen
DNA is the molecule that carries genetic information of a given organisms. Genetic variation is the changes that occur in the genome of an organisms to help an organism adapt well to the environment, however, they might also be disadvantageous. The variation in DNA sequences are useful in building a tree of life because DNA sequences are similar in closely related organisms and less similar in less closely related organisms.
<span>Valence is defined as number of electrons that are present in the outermost orbital. Oxygen is in the 16th column of the periodic table and the total number of valance electrons is determined by units place digit of the column position which is 6 for oxygen. The outermost orbital is the high energy level and there are two in that orbit. So the valance is +2.</span>
The answer is C since heterotroph means they don't have a way of making food
