Although the basic structure of the human body is the same for all people, there are many individual differences. You are well aware of the differences in the size and shape of people‘s head, neck, legs, arms, eyes, ears, and nose. Because of these differences, you can tell one person from another. The internal body parts of people also differ! Internal features vary from person to person just as the external features vary.

 

　　For example, the structure of the lungs of most people is basically the same, but lungs vary in shape, size, and weight from person to person.