Which best describes how ocean ridges form? a. decaying materials filter from above, creating ridges. b. corals grow on a submerged rim, forming circular ridges above the water. c. the flat action of the water shears off the top of a seamount, creating a ridge. d. magma pushes upward from inside the earth and adds new material to the ocean floor, creating a ridge.

Option (D)

Explanation:

The two plates move in the opposite direction in a divergent type of plate motion as a result of which seafloor spreading takes place where the magma is forced to come out to the surface of the ocean floor. This allows the addition of new materials to the crust, thereby forming the mid-oceanic ridge. This type of plate boundary leads to the formation of volcanoes and deep-focus earthquakes are often generated.

Thus, the mid-oceanic ridge is formed when magma pushes upward and adds new materials to the crust.

Hence, the correct answer is option (D).