Final answer:
Introducing an up into the left nostril helps facilitate nasal breathing and prevents particles from entering the body at an earlier stage.
Step-by-step explanation:
Introducing an up into the left nostril while holding the tube coiled in the right-hand helps facilitate nasal breathing and prevents particles from entering the body at an earlier stage.
Air enters the respiratory system through the nose, and as it passes through the nasal cavity, mucus and hairs trap any particles in the air. The nasal cavity is also lined with a mucous membrane and glands that produce mucus to help trap particles and microorganisms for removal. Additionally, the air is warmed and moistened in the nasal cavity, which helps protect the delicate tissues of the lungs.
By introducing the up into the left nostril, positive pressure is applied to the left side, which increases the upward flow of air, causing water to move to the right side of the tube.