Which of the following is a characteristic of hydrophilic molecules?

Hydrophilic molecules are characterized by their ability to interact favorably with water. This property is primarily due to their polar functional groups that can form hydrogen bonds with water molecules. As a result, they readily dissolve in water, allowing them to participate in biological processes where water is a solvent. This characteristic is essential in biological systems, as many biochemical reactions occur in aqueous environments, making the solubility of substances critical for metabolism and cellular functions.

In contrast, non-polar substances do not interact well with water and tend to be hydrophobic rather than hydrophilic. The other options either describe properties inconsistent with hydrophilic behavior or refer to interactions that do not define hydrophilic molecules directly. Thus, the ability to readily dissolve in water is the definitive characteristic of hydrophilic molecules.