Answer:
I believe the answer is A & B.
Explanation:
If it only allows you to pick one, i suggest picking A.
Answer:
Sodium chloride removes proteins from DNA and helps in DNA precipitation.
Explanation:
The Deoxyribonucleic acid (DNA) is negatively charged due to the highly polar phosphate groups that make up the phosphate backbone. The molecules of water are also highly polar and they have positive charge, thereby water molecules interact with the negative charges of the DNA. The sodium chloride generates temporary attraction forces between sodium (positive) ions and the DNA backbone (negative), thereby DNA can be disassociated from the aqueous layer. Moreover, sodium chloride helps to remove proteins (histones) that bound to DNA and also helps to maintain proteins in the aqueous layer.
