Which statement about the composition of ocean water is true? A. When surface water becomes more dense than the water below, the surface water sinks, which is called an ENSO. B. When surface water becomes more dense than the water below, the surface water sinks, which is called upwelling.
C. A water column with greater density differences between the layers is more stable than one with smaller density differences between the layers.
D. A water column with smaller density differences between the layers is more stable than one with greater density differences between the layers.