Question

Volcanic rock shows that some layers have magnetic fields that are aligned opposite to Earth’s. This evidence BEST fits which hypothesis?
Responses
A Earth's rotation has reversed in the past.Earth's rotation has reversed in the past.
B Earth's magnetic field has reversed in the past.
Earth's magnetic field has reversed in the past.
C Earth did not have a magnetic field until recently.Earth did not have a magnetic field until recently.
D Earth's magnetic field has always had the same orientation.Earth's magnetic field has always had the same orientation.

Answer 1

B. Earth's magnetic field has reversed in the past.

Explanation: As volcanic rock (lava) cools, magnetic minerals lock in the direction of the Earth's magnetic field at that time. Opposite alignments in different layers indicate the geomagnetic field has switched polarity (reversed) over geological time.