Prove that the increase in the complexity of the skeleton of amphibians is associated with a change in habitat.

Amphibians are the first land animals. To move on land, they have new sections of the skeleton – these are free front and hind limbs. The bones in them are connected by joints and consist of three sections. To attach the limbs to the skeleton, the structure of their belts has become more complicated, since they also serve as a support. The number of bones in the skull and spine has decreased, which made the body more compact for ease of movement on land. A cervical vertebra has appeared, allowing you to tilt your head.