• Why can’t most people move their ears?
  Humans, like most other animals, have a muscle behind each ear. ...

• How do muscles work?
  Muscles work by contracting. This makes them shorter and thicker so ...

• Why does exercise make muscles stronger?
  A muscle is made of bundles of fibers that contract when you use the ...

• How many bones do you have?
  As a baby you had over 300 bones, but, as you grow, some bones join ...

• Why do joints not squeak?
  Joints are cushioned by soft, squashy cartilage. Many joints also ...

• Why do people have different colored eyes?
  The iris is the colored ring around the pupil. The color is formed by ...