Final answer:
The ectoderm is the primary germ layer responsible for giving rise to the skin cells, as well as the nervous system and sensory organs.
Step-by-step explanation:
The skin cells are derived from the ectoderm layer of the embryo. The ectoderm is one of the three primary germ layers, alongside the mesoderm and endoderm, which give rise to all adult tissues and organs during embryonic development. While the ectoderm is responsible for forming the central and peripheral nervous systems, sensory organs, epidermis, hair, and nails, it is specifically this germ layer that gives rise to the skin cells. The mesoderm develops into the skeleton, muscles, connective tissue, heart, blood vessels, and kidneys. The endoderm forms the epithelial lining of the gastrointestinal tract, liver, pancreas, and lungs.