Abyssal Plains and hills

1.An AP is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 meters.
2.AP's are found laying beyween the foot of a continental rise and a mid-ocean ridge.
3.Consist of beds of volcanic rock topped with sediments that are up to thousands of feet thick. Flattest, smoothest, least explored regions.
4. AP's take up to 50% of the earth.