23. Which of the following statements BEST integrates the structural and physiological function of human skin as an organ? (A) The epidermis is a vascularized epithelial layer composed primarily of fibroblasts that provide tensile strength and thermal insulation. (B) Melanocytes located in the dermis synthesize keratin, which forms the main waterproof barrier of the skin. (C) The hypodermis is derived from ectoderm and is responsible for forming the stratified squamous epithelium of the skin. (D) Adipocytes in the epidermis secrete collagen fibers that anchor the skin to underlying muscle tissue. NTHU115 (E) The dermis contains connective tissue, blood vessels, sensory receptors, and glands, enabling skin to function in protection, sensation, and thermoregulation.