The force of attraction between water molecules is known as which?

• A. Adhesion
• B. Cohesion
• C. Surface tension
• D. Osmosis

Answer: (B)

The main idea here is cohesion—the attraction between water molecules themselves. Water molecules are polar and form hydrogen bonds with one another, so each molecule pulls on its neighbors. This bonding among like molecules is what we call cohesion, and it’s the direct force keeping water molecules together.

This is the best fit because cohesion specifically describes the attraction between molecules of the same substance, which is exactly what water molecules do to each other. Adhesion, by contrast, is the attraction between water and other substances (like a glass surface). Surface tension is a consequence of cohesive forces at the surface, giving water that “skin-like” layer, but it’s not the name for the attraction itself. Osmosis is the movement of water across a membrane driven by differences in water potential, not the mutual attraction between water molecules.