<prompt> All are true regarding trachea EXCEPT?Has C shaped cailagesOuter diameter is 2 cmMore than 20 hyaline cailagesIsthmus of thyroid gland lies at 2, 3 and 4th tracheal rings  <response>: Trachea Length - 10- 15cm Diameter - 2cm males, 1.5cm females Upper end - at lower end of cricoid cailage. Lower end - sternal angle C6 - T6 erect position in living person. Fibroelastic wall. Cailaginous skeleton suppoed by 16 - 20 C- Shaped rings. Lumen lined by ciliated pseudostratified columnar epithelium 