Concept:Cohesion is the attraction between molecules of the same substance, such as water molecules attracting one another.Explanation:Water molecules stick to one another because of hydrogen bonding.This mutual attraction between water molecules causes them to stay together and form droplets or beads.Option D directly describes water molecules sticking to one another, which is cohesion.The other options describe adhesion, which is the attraction between water and a different surface.Answer:D. Water molecules stick to one another and form a bead.