Name the animals that have an external and internal skeleton.

The internal skeleton is characterized by the fact that it is hidden under the skin and muscles. We cannot see part of the skeleton of the animal. Mammals, birds, amphibians, and other chordates have this type of skeleton. Mollusks and others have an external skeleton. These are animals that have open parts of the support system. Do not confuse the teeth with the skeleton. Although we see them and they are not hidden under the skin, teeth are not skeletal. They have a completely different structure and nature of origin. Therefore, animals with teeth cannot be classified as organisms with an external skeleton.