Answer: Structural ; proper growth.
Step-by-step explanation:
Shedding of the upper layer of skin in snakes is an example of structural adaptation. This is because it helps in growth of snakes. This is a normal function that occurs in every snakes for their proper growth and development.
The skin of snakes stops it from growing and that is why the snakes need to shed off the uppermost part of their skin.
This adaptation allows further growth and removes parasites that may have attached on the older skin. As the animal grows the skin stretch and the older skin need to be shed off. This process is known as ecdysis.