Question

sea - floor spreading takes place where
a mid - ocean ridge
b trenches
c pangaea
d continental drift

Explanation:

Sea - floor spreading occurs at mid - ocean ridges where new oceanic crust is formed as tectonic plates move apart. Trenches are areas of subduction. Pangaea is the supercontinent that existed in the past. Continental drift is the theory of the movement of continents.

Answer:

A. Mid - ocean ridge