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.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.