Answer:
The solubilities in water of the three molecules from most to least soluble is in the following order: phosphate > deoxyribose > guanine.
Step-by-step explanation:
The phosphate group is the most water-soluble due to it being very much negatively charged .
The deoxyribose which has several hydroxyl groups, is the next most water-soluble molecule.
The guanine molecule is hydrophobic, therefore, it is the least soluble in water.
A DNA molecule is composed of the three molecules: deoxyribose sugar, a phosphate group and a nitrogenous base which could either be a purine or a pyrimidine.
The three dimensional structure of DNA is such that the the phosphate groups and deodyribose sugars form the backbone of the structure on the outside of the DNA double helix where they are exposed to the aqueous environment of the nucleus. On the other hand, the hydrophobic nitrogeneous bases are located in the interior of the double helix where they are excluded from excludedthe aqueous environment of the nuclues. This structural arrangement is in accordance with the solubility of the molecules where the water-soluble phosphates and sugars are exposed to water while the water-insoluble bases are away from water.