ANATOMY

Detailed explanation-1: -The tracheal rings and lung mesenchyme derive from the mesodermal germ layer, as the endoderm only forms the epithelial lining of the respiratory tree.

Detailed explanation-2: -The mesoderm (middle layer of an embryo) helps give rise to the remaining components of the lungs. Specifically, the splanchnopleuric mesoderm, gives rise to: the vasculature, connective tissue, muscle, and cartilage associated with the bronchi, and the pleura of the lungs.

Detailed explanation-3: -Trachea. The epithelium and glands of the trachea develop from the endoderm of the laryngotracheal tube. The cartilage, connective tissue, and smooth muscle are derived from the surrounding splanchnic mesenchyme.