Which layer of skin is primarily composed of connective tissue and fatty tissue?

The subcutaneous layer is primarily composed of connective tissue and fatty tissue, which serves several important functions for the body. This layer, also known as the hypodermis, provides insulation, acts as a cushion, and helps anchor the skin to the underlying structures such as muscles and bones. The presence of adipose tissue in the subcutaneous layer contributes to energy storage and plays a role in thermoregulation by providing heft against temperature changes.

In contrast, the epidermis is the outermost layer of skin and is primarily made of keratinized epithelial cells, which serve as a protective barrier. The dermis, situated below the epidermis, contains connective tissue but is distinct from the subcutaneous layer in that it also houses blood vessels, hair follicles, and various glands. The stratum granulosum is a specific layer of the epidermis involved in keratinization and is not composed of connective tissue or fatty tissue. Thus, recognizing the composition and functions of each skin layer clarifies why the subcutaneous layer is the correct answer in this context.