Which statement about Earth's inner core is true?

Which statement about Earth's inner core is true?

• A. The inner core is solid.
• B. The inner core is liquid.
• C. The inner core is gas.
• D. The inner core does not exist.

Answer: (A)

Extreme pressure inside Earth keeps the inner core solid. Even with incredibly high temperatures near the center, the immense pressures at Earth's center force iron to stay in a solid phase. Seismic data help confirm this: S-waves don’t travel through liquids, and the outer core is identified as liquid while the behavior of waves near the center matches a solid region. So the true statement is that the inner core is solid. It’s not liquid or gas, and it does exist as a distinct solid sphere at the center, surrounded by a liquid outer core.

Extreme pressure inside Earth keeps the inner core solid. Even with incredibly high temperatures near the center, the immense pressures at Earth's center force iron to stay in a solid phase. Seismic data help confirm this: S-waves don’t travel through liquids, and the outer core is identified as liquid while the behavior of waves near the center matches a solid region. So the true statement is that the inner core is solid. It’s not liquid or gas, and it does exist as a distinct solid sphere at the center, surrounded by a liquid outer core.