Which statement best describes the Earth's outer core?

• A. It is a liquid layer that generates Earth's magnetic field
• B. It is a solid layer that does not conduct electricity
• C. It is a liquid layer that creates volcanoes
• D. It is a gas layer

Answer: (A)

The outer core is a molten layer of iron and nickel that remains liquid under the extreme heat inside Earth. Because this liquid metal moves and conducts electricity, it acts like a dynamo, generating Earth’s magnetic field as the conducting fluid flows and twists. This magnetic field is what makes compasses point toward the magnetic north. It’s not solid, so it can keep circulating and producing the field, and it’s not a source of volcanoes (those come from the mantle), nor a gas layer. So the statement that best describes it is that it is a liquid layer that generates Earth's magnetic field.