6.+Unicellular+and+multicellular+organisms

__Unicellular and Multicellular Organisms__

 * Definitions: Unicellular organism - a living thing made of one cell**
 * Multicellular organism - a living thing made up of many cells**

There are many types of living things composed of just one, single cell. These organisms are called unicellular organisms. Obviously they are very small and in some cases there may be millions of them living in a single drop of water.



All the familiar plants and animals are multicellular. They are made up of billions of cells. The cells are all pretty much the same size. For example, the cells in a mouse are exactly the same size as the cell in an elephant. The elephant simple has a lot more cells. In a multicellular organism, however, each part of the body is specialised to do a particular job, and usually has many specialist cells. For example, muscle cells are different to nerve cells, and blood cells are different again.



**BLAH** 1. Add the definition for multicellular organism AND unicellular organism to your wordlist. 2. Add your comment to the discussion for this page.
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