Answer:
The inner core is a hot, dense ball of (mostly) iron.
Explanation:
Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km, which is about 20% of Earth's radius or 70% of the Moon's radius. There are no samples of Earth's core accessible for direct measurement, as there are for Earth's mantle.
