Final answer:
Nasal breathing is preferred over mouth breathing because the nasal passages filter particles out of the air more effectively.
Step-by-step explanation:
Nasal breathing is generally preferred over mouth breathing because the nasal passages do a better job of filtering particles out of the air before it reaches the respiratory tract. The hair-lined nasal passages trap and remove particles, reducing the chances of them entering the body. In contrast, breathing through the mouth allows particles to pass through without filtration, increasing the risk of them entering the body.