Which of the following describes subcutaneous tissue?

Subcutaneous tissue, also known as hypodermis, is primarily composed of fat cells, connective tissues, and larger blood vessels. This layer plays a critical role in storing fat, which serves as both insulation and energy storage. It is situated beneath the dermis and effectively helps to regulate body temperature by trapping heat and protecting underlying muscles and bones.

The other options describe functions or characteristics of different skin layers or components. The epidermis is the outermost layer of skin that connects to the dermis, while the dermis plays a vital role in hydration and contains structures that act as barriers against pathogens, including immune cells. Moisture regulation is mostly managed through sebaceous glands in the dermis, further distinguishing the unique functions of each skin layer. This comprehensive understanding underscores why subcutaneous tissue is important mainly for fat storage and insulation.