Consider the following statements relating to hydrostatic forces on the submerged surface :

1. The pressure center is always below the centroid of any plane-submerged surface that is not horizontal.

2. Total force on a curved surface is the product of the average force and the submerged area.

3. The magnitude of hydrostatic pressure at a particular depth is a function of the shape of the surface.

4. The vertical component of force on a body completely submerged in a static reservoir of fluid is equal to the weight of the fluid displaced by the body.

Of these statements