What is the complication of the organization of reptiles in comparison with amphibians?

1) dry skin without glands with horny formations, providing protection against moisture loss in the body;
2) breathing only with the help of the lungs having a cellular structure, which increases the area of ​​gas exchange in the lungs and its intensity;
3) the appearance in the three-chamber heart of an incomplete septum in the ventricle, so the blood is partially mixed;
4) internal fertilization, the appearance in the egg of a supply of nutrients and protective membranes makes it possible to multiply on land;
5) the complication of the nervous system and sensory organs, the development of the forebrain provide more complex reptile behavior and communication with the external environment;
6) an increase in the number of vertebrae of the cervical spine, allowing not only to raise and lower the head, but also to turn it.