Why do scientists think the Grand Canyon was once covered by an ocean?(1 point) Responses The Grand Canyon is located along coastlines that likely flooded. The Grand Canyon is located along coastlines that likely flooded. Seawater has been found seeping up through the canyon floor. Seawater has been found seeping up through the canyon floor. The sedimentary rock type forming layers of the canyon formed under the sea. The sedimentary rock type forming layers of the canyon formed under the sea. Only an ocean would have the strength to erode the rock forming the Grand Canyon.