What is the main function of the hypodermis?

The hypodermis, also known as subcutaneous tissue, plays a crucial role in insulating the body. It is primarily composed of loose connective tissue and fat cells, which trap heat and help maintain a stable body temperature. This insulation is essential for protecting the body from extreme temperatures and helps in energy storage. Additionally, the hypodermis serves to cushion underlying structures such as muscles and bones, while also anchoring the skin to the underlying tissues.

The other options, while significant in their own right, do not capture the primary function of the hypodermis. Structural support is more closely associated with deeper layers of the skin and connective tissue. While some vitamins are stored in fat tissues, this is not the main role of the hypodermis. Hormonal generation is a function of specific glands rather than a function of the hypodermis itself. Thus, the primary and most relevant function of the hypodermis in the context of this question is its role in body insulation.