Question

which is the first step in the seafloor spreading process? a crack forms in oceanic crust. volcanoes erupt under the ocean. molten rock rises up through the crust. dense plates are subducted under less dense plates.

Explanation:

Seafloor spreading starts with a crack forming in the oceanic crust. This allows magma to well - up later. Volcanoes erupting, molten rock rising, and plate subduction are later steps in related geological processes but not the first in seafloor spreading.

Answer:

A. A crack forms in oceanic crust.