2.3

Tides and ocean currents: Twice each day, the level of the seas and oceans rises and falls, in a pattern determined by the alignment of Earth, Moon and Sun. The magnitude of these changes in level, known as tides, is also affected by environmental factors such as winds. Winds and temperature, along with other factors, also give rise to ocean currents. These currents ensure that the water in all the world�s oceans is able to mix, via the global ocean conveyor belt.