What do all insects have in common?

One thing that all insects have in common is that they all have three body regions. They all also have jointed legs.

Insects all contain a head, a thorax and an abdomen. These may vary in size and color, but they can be found in nearly every insect on the planet. Each segment of the body has a cuticle in place which helps the body bend and move. The cuticle stays the same size until the insect sheds and regrows it. All insects also have a breathing system which contains a tube. This tube allows them to take in and expel air.