Currents are also shaped by ___ ___ which impedes the flow.

• A. Sea floor
• B. Ocean trenches
• C. Continental shelves
• D. Land masses

Answer: (D)

The movement of currents is shaped by obstacles in the ocean, with landmasses acting as major barriers. When water generations of wind-driven flow meet continents, they cannot pass through, so the currents are redirected along coasts and around the edges of the land. This blocking effect helps create the large circular patterns known as gyres and guides boundary currents like those along the coast, shaping how surface water moves across basins. While features on the sea floor, such as trenches or shelves, influence deeper or near-bottom flows, they don’t determine the broad surface-current pathways as strongly as the presence of landmasses themselves. So, land masses best complete the idea: they impede and redirect the flow of currents.