ABSTRACT
All animals and plants are made up of cells like a house is made up of bricks. Cells are the building blocks of life. Humans have at least 200 different types of cell inside them. Some specialized cells work together in large numbers to form organs such as the liver or tissues such as muscles. Like microbes, animal and plant cells are too small to be seen by the naked eye. They must be magnified at least 100 times (100X) in order to see them.
