Which concept is described in the theory proposed by Hess? Continents do not move. Cool rock pushes through the crust. Trenches are sites of seafloor spreading. Mid-ocean ridges are sites of seafloor spreading.

Mid-ocean ridges are sites of seafloor spreading.

Complete question;

Which concept is described in the theory proposed by Hess?

a. Continents do not move

b. Cool rock pushes through the crust.

c. Trenches are sites of seafloor spreading

d. Mid-ocean ridges are sites of seafloor spreading

Answer:

d. Mid-ocean ridges are sites of seafloor spreading

Explanation:

Harry Hammond Hess was a professor of geology. He was interested in the ways ocean floors are formed. His theory was regarded as sea floor spreading.

He discovered the ocean was shallower in the middle and located the mid ocean ridge. The mid oceanic ridge is where new ocean floor is formed. Magmatic material from the aesthenophere creep or erupt through the mid oceanic ridges to create a new ocean floor. He discovered the ocean floor spreads away from the ridge along the mid ocean ridge. He discovered that basaltic magma ooze from the aesthenosphere along this ridge.

The rocks formed closer to the ridge are more younger compare to those farther the ridge. He noted that the rocks becomes older as one moves away from the ridge. The concept of he proposed was that mid oceanic ridges are site of sea floor spreading.