Question

Snakes and lizards shed their scales as skin cast. It is
A. Dermis
B. Epidermis
C. Modified cells
D. Stratum germinativum

Answer 1

Hint:- Snakes and lizards belong to class reptilia. Scales are of different shapes and sizes and mostly help in the protection of reptiles from the outer environment. They mostly cover the skin of reptiles and help to retain moisture and change characteristics of the surface to provide support in camouflage like roughness

Complete step-by-step solution:-
Lizards and snakes are land reptiles. The skin serves as a protective boundary against the external climate. Scales are composed of both epidermis and dermis and the scales themselves are epidermal in ancestry. The epidermal layer of skin is made up of cornified cells, in case of reptiles like skin and lizards. The shedding of scales happens in the form of a continuous layer of skin. Hence, this process is known as Ecdysis.
In the process of Ecdysis, reptiles shed the scales having epidermal origin in the form of cornified cells. The process of shedding may take a few days or even weeks and mostly depends on the size, body situation and climate. The snake must remain peaceful or restful during the process of shedding. Even blindness may occur, if these thin layers of skin are not shed properly.
The deepest layer of the epidermis is the stratum germinativum. This layer is mainly composed of keratinized cells. Hence this layer divides continuously to replace the dead keratinized cells.
So, the correct answer is C.

Note:- Snakes and lizards excrete uric acid. Hence, they are Uricotelic organisms. It has been noticed that younger snakes shed their skin more repeatedly as they are growing. Before the shedding cycle, the snake releases a grease at the base of the peripheral layer of skin which aids the shedding cycle. In the eyes of snakes, this lubricant can be visible.