What does the following sentence imply?
"Because of the existence of forces across any line in the surface of a liquid, the surface tends to shrink whenever it gets a chance to do so."
Why does the existence of forces cause tendency to shrink the surface? I understand that the surface molecules have extra energy than the molecules in the interior, so lesser surface area means lesser surface energy(the extra energy), which is thermodynamically favourable. But how does the existence of forces relate to this?