Which embryonic layer is associated with developing the skin?

The ectoderm is the embryonic layer that is primarily responsible for developing structures of the skin as well as the nervous system. During early embryonic development, the ectoderm forms the outermost layer of the embryo, which eventually gives rise to not only the epidermis of the skin but also important features such as hair, nails, and the nervous system components, including the brain and spinal cord. This layer is crucial in establishing protective barriers and sensory functions in the organism.

In contrast, the mesoderm, which lies between the ectoderm and endoderm, primarily contributes to the development of the muscles, skeletal system, circulatory system, and some internal organs. The endoderm, being the innermost layer, is primarily associated with internal organs such as the gastrointestinal tract and respiratory system. The gastrula is not an embryonic layer but rather a developmental stage that occurs after the blastula, during which the layers of the embryo start to differentiate. Therefore, the ectoderm’s specific role in forming skin and various external structures makes it the correct answer in this context.