How does the topography of the seafloor give evidence for seafloor spreading?

The topography of the seafloor gives us a nice clue about the seafloor spreading. This can be seen in the highest of the underwater features. The mid-ocean ridge is the highest. It is the place where the magma comes out, cools off, and constantly creates new rocks, or rather crust. As we move further away from the mid-ocean ridge, we will notice that the sea mounds are getting smaller and smaller, but also more rounded, or flatter. This is an evidence of the erosion by the water. As the water erodes the crust, it loses on height, thus becomes less pointy, and more rounded or flatter. As we move even further away we will see that there's no more sea mounds, but it is only the old crust that is predominantly flat, which of course has been caused by the millions of years of erosion by the water. This was actually the first thing that has been noticed and that gave a clue to the scientists that maybe the seafloor is spreading, and with the further examinations of it, it turned out to be true.

not completely sure but i think it’s many moons, smaller in size and a ring system.