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structure of the biosphereclick to hear

Biosphere: the part of the Earth’s covering where life is possible; it extends from the floor of the oceans to the summit of the highest mountains (about 12 mi).
structure of the biosphere atmosphere hydrosphere lithosphere

atmosphere click to hear

Layer of air that surrounds the Earth and is composed mainly of nitrogen (78%) and oxygen (21%); only its lower portion is part of the biosphere.

hydrosphere click to hear

A collective term for the planet’s waters, including the oceans, seas, lakes, watercourses and underground water systems.

lithosphere click to hear

Outer layer of the Earth’s crust; only its upper portion, to a depth of 1 mi, is part of the biosphere.