The Earth exhibits a magnetic field that reaches above our atmosphere. Earth has a solid inner core and surrounding this is the outer core, a 2,000 km thick inner core that is fluid. Differences in temperature, pressure and composition within the outer core cause
convection currents in the liquid as cool, dense matter sinks whilst warm, less dense matter rises. The Coriolis force, resulting from
the Earth's spin, also causes swirling whirlpools. This movement of ions generates electric currents, which in tur produce magnetic
fields. Because of this we know that the outer core must be composed of
A)
plasma
B)
iron and nickel
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nickel and lead
D)
lead and mercury