How many parts of ocean relief are there?

The ocean floors can be divided into four major divisions: 

• The Continental Shelf
• The Continental Slope
• The Deep Sea Plain
• The Oceanic Deeps. 

Besides, these divisions there are also major and minor relief features in the ocean floors like ridges, hills, seamounts, guyots, trenches, canyons, etc.

Further Reading:

• Ocean Floor And Its Features
• Minor Relief of the Ocean floor