Most living things are made up of one or more cells. Some organisms are composed of only one cell, and others are made up of millions of different kinds of cells. These are cells that have been grown in a dish, and so they can stick down and spread out if they want to.
Some cells grow easily and can even form tissues in a dish.
Culturing cells makes it easy for us to study them, and to do things like test medicines for diseases and treatments for cancer. This material may not be reproduced in any form without express written permission.