Explanation:
As a substance melts, and goes from a solid to a liquid state, the kinetic energy of the molecules increases, and the molecules move faster, and they separate further and further away from each other. The intermolecluar forces holding the molecules together become weaker
Purines are adenine and guanine. So the answer should be D (Pyrimidines). besides, phosphate group and pentose sugar are a part of a nucleotide.
