Consider the following statements:

1. Ocean currents involve the continuous flow of large quantities of water in a definite direction.
2. In waves, the same body of water generally moves forward with the wave train across the ocean.
3. Tides represent the periodic rise and fall of ocean water.
4. Upwelling of subsurface water and sinking of surface water are forms of vertical ocean-water movement.

Which of the statements given above are correct?