What features of the structure of the skin in reptiles make it impossible for them to participate in respiration?

Reptiles are animals belonging to the class Vertebrates. Reptile skin consists of two layers – the inner and outer layers. The outer layer of reptile skin becomes keratinized over time and forms scales that fit tightly to each other. This property allows reptiles to maintain body temperature and skin moisture. However, this structure of the skin prevents air circulation through the skin. Therefore, the skin of reptiles cannot participate in the breathing process and is not an organ of the respiratory system.