Ocean currents are divided into _________ main categories.

___________ account for 97.2% of the Earth's water.

___________ is high in silica and thicker,piles up around the vent and explodes to form cones.

North Atlantic Drift,Gulf Stream and Brazilian Current etc are the examples of ___________.

_____________ has an average thickness of about 60 km.

Planetary winds and the differences in the density of sea water are the primary causes for the movement of __________.

The ___________ is the smallest of all the oceans.

____________ contains 75% of the atmosphere's gases and large amount of water vapour and dust.

___________ layer is warm near the surface of Earth.

The _____________ is thicker under the continents than under the ocean floor.