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HUMAN BODY

The body is often divided into body systems. Each system, though performing specific jobs, works together with the other systems. Body systems are made from microscopic building blocks, called cells. A typical cell is only 0.011 inches across. There are about 10 trillion cells in the body. There are many different kinds of cells, such as nerve cells and muscle cells. Many cells of the same kind form tissue, such as nerve and muscle tissue. Two or more different kinds of tissue create an organ, like the brain, stomach, or kidney. Several organs working together to carry out one major function, such as digesting food, are known as a.