a. phosphate group, sugar, nitrogen base.
b. if it is DNA- deoxyribose sugar and if it is RNA- ribose sugar
c.Nitrogen base
d. Adenine, Gaunine, cytosine, Thymine.
In my opinion, the correct answer among the choice given above is option D. It is advantageous for grazing mammals to gather in groups because groups <span>offer greater protection from predation. It protects them because predators will think twice in nearing the group because it is outnumbered.</span>
The smallest and most exclusive grouping category is species.
