Distinguish between:

3.  Bank and Reef.

Bank

Reef

A bank is more or less flat topped elevation located on the continental margins. The depth of water over bank is relatively small but is adequate for navigation. The Dogger Bank in the North Sea and the Grand Bank in the North-Western Atlantic off Newfound land and George's Bank off the eastern coast of U.S.A. are famous examples of Banks.

A reef is a rocky or coral elevation having a generally elongated shape. There are many well known types of reefs such as Fringing Reef, Barrier Reef, Coral Reef and Atoll Reef. The longest barrier reef extends off the Queensland coast of Australia.