Question

1. during sea floor spreading, molten material rises up from the mantle...

deep ocean trenches
along the continents
at the mid ocean ridges
at north and south poles

Explanation:

Sea - floor spreading occurs at mid - ocean ridges. Mid - ocean ridges are underwater mountain ranges. At these ridges, magma (molten material) from the mantle rises up. As the magma cools, it forms new oceanic crust. Deep ocean trenches are associated with subduction (where one tectonic plate is forced below another). Along the continents is not the specific location for sea - floor spreading. The north and south poles are not the sites of sea - floor spreading.

Answer:

C. At the mid ocean ridges