Answer:
1) Phosphate
2) Nitrogen bas
3) First carbon
Step-by-step explanation:
In base pairing and stacking of nucleic acid strand, we have nitrogen base pair, pentose sugars, and phosphate groups.
The phosphate group is attached to the 5' carbon atom of the sugar portion of a nucleotide and the nitrogen group is attached to the first carbon atom of the sugar potion of the nucleotide.