The____enters the nose (and mouth). In the nasal passages, the entering air is made____, _____and_____of unknown particles. Next, the air moves down through the ______, the empty tube that serves as_____ of air into the lungs. _____ are the two branching tubes that ____the trachea to the lungs._____are the hair- like tubes that_____ to the alveoli. Alveoli are the_____that allow_____ in lungs. The_____is the muscle that____ the breathing process.