Why do scientists think the Grand Canyon was once covered by an ocean?

A: The Grand Canyon is located along coastlines that likely flooded.
B: Only an ocean would have the strength to erode the rock forming the Grand Canyon.
C: the sedimentary rock type forming layers of the canyon formed under the sea.
D: Seawater has been found seeping up through the canyon floor.

1 answer

C: the sedimentary rock type forming layers of the canyon formed under the sea.