Pharyngeal Arches and Pouches

Which pharyngeal pouch gives rise to the epithelium of the auditory tube and middle ear cavity?

Which feature best distinguishes the derivatives of the 2nd pharyngeal arch from those of the 1st pharyngeal arch?

The muscles of mastication are innervated by which branch of the trigeminal nerve, and from which pharyngeal arch do they originate?

A 3-year-old boy presents with a painless swelling in the anterior triangle of the neck that has been present since infancy. On examination, the swelling is soft, compressible, and transilluminates. Ultrasound confirms a cystic lesion. The parents are counseled about the embryological origin and management. What is the most appropriate next step in management?

A 3-year-old boy from Mumbai presents with a painless swelling in the anterior triangle of the neck, just below the angle of the mandible. On examination, the swelling is soft, compressible, and transilluminates. The child has a history of recurrent upper respiratory tract infections. Imaging confirms a cystic lesion. Which embryological structure failed to obliterate, resulting in this presentation?