Insects are the most successful creatures in the entire animal kingdom. They are very adaptable and live everywhere - on land, in the air, and in and on water. They are also very small, so they can fit into small places and do not need a lot of food to survive.
Insects are invertebrates - they have no backbone.
However insects are different from other anthropods because they only have six legs. These other anthropods include millipedes, wood lice and spiders. Most insects also have wings, in fact they were the first creatures to fly. Their wings allow them to escape from danger and search for food over a wide area. Insects also use their wings when finding and attracting a mate - for instance by making a noise with them.