What is the similarity of the bottom topography of all the oceans of the Earth?

At the bottom of all the oceans of the Earth there are mountain ranges, rocky outcrops, deep crevasses with steep walls, deep rift valleys, and underwater canyons. The continental shelf is also not even, as it might seem at first glance, rocky ledges are common on its outer parts. Depressions and hollows are noted on the shores that are often subject to glaciation on the shelf.