The correct answer is A. Epidermis.
The epidermis is the outermost layer of skin. It is made up of several layers of cells that are constantly being shed and replaced. The epidermis is responsible for protecting the body from the environment, and it also helps to regulate body temperature.
The dermis is the layer of skin that lies beneath the epidermis. It is made up of connective tissue, blood vessels, nerves, and hair follicles. The dermis is responsible for providing support and structure to the skin, and it also helps to regulate body temperature.
The hypodermis is the layer of skin that lies beneath the dermis. It is made up of fat cells, and it helps to insulate the body and protect it from injury.
Tissues are groups of cells that are similar in structure and function. They are the basic building blocks of the body, and they work together to perform the many functions that are necessary for life.