Which layer of skin constantly replaced by new cells?

The correct option is A Epidermis

• The cells in the superficial or upper layers of skin, known as the epidermis, are constantly replacing themselves.
• This process of renewal is basically exfoliation (shedding) of the epidermis.
• But the deeper layers of skin called the dermis, do not go through this cellular turnover and so do not replace themselves. Hence, Epidermis is the layer of skin that is constantly replaced by new cells.

So, the correct answer is 'epidermis'.