<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> The continental shelf is an underwater landmass which extends from a continent, resulting in an area of relatively shallow water known as a shelf sea . Much of the shelves were exposed during glacial periods and interglacial periods . </P> <P> The shelf surrounding an island is known as an insular shelf . </P>

The shallow region of the ocean that occurs above the continental shelf