'The inner core of the Earth is thought to be a solid ball composed mainly of nickel & this metal'
iron
THE EARTH: The inner core of the Earth is thought to be a solid ball composed mainly of nickel & this metal
The inner core of the Earth is thought to be a solid ball composed mainly of nickel & this metal
The inner core of the Earth is thought to be a solid ball composed mainly of nickel & this metal
THE EARTH
iron
THE EARTH