Which embryonic layer gives rise to connective tissue?

The correct answer, which identifies the mesoderm as the embryonic layer that gives rise to connective tissue, highlights the role of this layer during embryonic development. The mesoderm is one of the three primary germ layers formed during gastrulation, alongside the ectoderm and endoderm.

From the mesoderm, a wide variety of tissues and structures develop, including not only connective tissues like cartilage, bone, and blood, but also muscle tissue and components of the circulatory, excretory, and reproductive systems. This functionality makes the mesoderm critical for the formation of the body's structural and supportive systems.

Regarding the other options, the ectoderm primarily develops into structures like the skin and nervous system, the endoderm gives rise to internal organs such as the gastrointestinal tract and respiratory system, and the neuroectoderm specifically contributes to the development of the nervous system. None of these layers are responsible for forming connective tissues, thus reinforcing the significance of the mesoderm in this aspect of embryonic development.