<prompt> Eustachian tube develops from:2nd and 3rd pharyngeal pouch1st pharyngeal pouch2nd pharyngeal pouch3rd pharyngeal pouch  <response>: Pharyngeal Pouch Derivatives 1 Tympanic middle car cavity, auditory eustachian tube 2 Palatine tonsils, tonsillar fossa 3 Inferior parathyroid gland, thymus 4 Superior parathyroid gland, ultimobranchial body parafollicular C cells of thyroid 