The correct answer is option 4, surface tension. Soaps clean surfaces based on the principle of surface tension. Surface tension is the property of a liquid that causes it to minimize its surface area by forming a film or layer on top.

When soap is applied to a surface, it reduces the surface tension of water. As a result, the water spreads out more evenly and penetrates into microscopic crevices and pores. This allows the soap to loosen dirt, oils, and other substances that are stuck to the surface.

Soap molecules consist of a head and a tail. The head is hydrophilic, meaning it is attracted to water, while the tail is hydrophobic, or repelled by water. When soap is mixed with water, the hydrophilic heads are attracted to the water molecules, while the hydrophobic tails are repelled by the water. This causes the soap molecules to arrange themselves in a way that forms a layer between the water and the dirt or oil on the surface.

As a result of this arrangement, the dirty or oily substances are lifted off the surface and surrounded by the soap molecules. They can then be rinsed away with water, leaving the surface clean.

In summary, soaps clean surfaces based on the principle