Assertion: magnetic field's core | /r/HasProperty | iron
Facets:
value: mostly
type: DEGREE
Source sentences:
text: There, the heat of the Earth's solid inner core churns a liquid outer core composed of iron and nickel.
text: Earth owes its magnetic field to its molten outer core, which is made mostly of iron and nickel.
text: There, the heat of the Earth's solid inner core churns a liquid outer core composed of iron and nickel.