What body of land is smaller then the contenent and is completely surrounded by water

An island.

what's the nothermost and the southernmost points in the world called?

It looks as if you need to learn to use a good search engine.

Go to http://www.google.com and enter the following:

northernmost point of world

southernmost point of world

You can do this with all your questions although you may have to tweak the search words occasionally.

If you need further help learning how to search, including how to choose good search terms, go here and scroll down to the links under HOW TO SEARCH THE INTERNET:
http://hanlib.sou.edu/searchtools/

=)

The body of land that is smaller than a continent and completely surrounded by water is called an island. To find this answer, you can go through a process of elimination and apply basic geographical knowledge.

Start by understanding the definition of a continent. Continents are the largest landmasses on Earth and are typically distinguished by their size and geological features. There are seven continents: Africa, Antarctica, Asia, Europe, North America, Australia, and South America.

Next, consider the requirement of being completely surrounded by water. Continents typically share borders with other continents or larger bodies of land. However, islands are isolated landforms that are surrounded by water.

By combining these two pieces of information, we can conclude that the body of land smaller than a continent and completely surrounded by water is an island.