Skeletons support the body and allow it to move. It also protects vital organs (e.g. heart).
Vertebrates are organisms with a backbone and an internal skeleton, such as fish, amphibians, reptiles, birds and mammals.
Some animals are invertebrates, which means they have an external skeleton and no backbone. These include ants and other insects.
Internal skeletons have some advantages over organisms with external skeletons, and these are;
- it easily grows with the body
- it's easy to attach muscles
- it's more flexible
- gives the body a supporting framework.
Bones are made from living cells, which means they can grow and repair themselves if necessary.
Long bones are hollow, which makes them lighter for the organism, allowing them to move more efficiently.
This hole in…