Answer:
The structure that holds the air passages open in the trachea (windpipe) is the hyaline cartilage in the tracheal wall offering support and keeping the trachea drom collapsing.
Step-by-step explanation:
The bronchi are divided in two by the level of the fifth thoracic vertebra the gaps that keeps the bronchus open are the cartilages filled with the trachealis muscle, that holds open the lumen of the trachea and bronchis and allow the flexibility necessary for the respiration motion (inspiration and expiration).