Answer:
molecules at the interface form stronger inward bonds
Step-by-step explanation:
The hydrogen bonds between molecules of water cause water molecules to strongly aggregate in the bulk of the liquid, however, at the air-water boundary, water forms stronger inward bonds of which the strong cohesive forces between the water molecules as opposed to the attraction of the water molecules to the air is responsible for this. Water molecules on the surface have no neighbours so they exert the greatest inward force.