Calcite and aragonite are both calcium carbonate minerals, but have different atomic structures.

Many mid-ocean ridges are shallower than the CCD, and so do not have mantles of calcite tests deposited on top of them.

The Mediterranean Sea is less saline than the average ocean.

Organisms can readily expel elemental mercury (the silver liquid) from their tissues, but cannot readily expel methylmercury.  

A cotidal line links the points on the ocean where high tide occurs simultaneously.

The shelf break is where turbidity currents generally slump from.

The Solar Day is shorter than the Lunar Day.

Protozoans are microscopic animals that are photo-synthetic.

The ecliptic is the line corresponding to the axis on which the Earth spins.

The Coriolis Effect deflects moving objects to the left in the Northern Hemisphere