How does Earth's magnetic field provide evidence for seafloor spreading?

a. It creates a pattern of alternating rock stripes on both sides of a mid-ocean ridge.

b. It allows scientists to determine the age of drilling samples.

c. It causes magma to harden quickly underwater.

d. It shows that younger rocks are located deeper underwater than older rocks.

a. It creates a pattern of alternating rock stripes on both sides of a mid-ocean ridge.

Explanation:

Seafloor spreading is the theory that the oceanic lithospheric plates are in constant motion just as continental drift occurs.

When oceanic plates collide, the denser subducts under the less dense one, causing a destruction of oceanic lithosphere.

However, during seafloor spreading, a rift in the ocean can spill out some of the partially melted subducted rock. When the magma cools, there is an alternation in the magnetic variation of rocks formed by the series of volcanic action that has occurred underwater.

The variation shows younger rocks closer to the mid-oceanic ridge formed in the process. This variation is measured and compared to confirm that sea floor spreading has actually occurred.

a. It creates a pattern of alternating rock stripes on both sides of a mid-ocean ridge.