What does Pascal's principle state about fluids?

Pascal's principle states that when pressure is applied to an enclosed fluid, that change in pressure is transmitted undiminished throughout the fluid in all directions. This means that if you apply pressure at any point in the fluid, all parts of the fluid will experience the same increase in pressure uniformly. This principle is particularly important in hydraulic systems, where a small force applied to one area can create a larger force in another area, as the pressure is the same throughout the fluid.

The other options reflect common misunderstandings about fluid behavior. Pressure in a fluid does indeed vary with depth, where deeper layers experience greater pressure due to the weight of the fluid above them. While fluid pressure can be constant when a fluid is at rest, this alone does not capture the essence of Pascal's principle. Finally, fluids exert pressure in all directions, not just one, which contradicts the idea presented in another option. Pascal's principle emphasizes the transmission of pressure regardless of the direction, highlighting its critical role in the mechanics of fluids.