Answer:
1. b 2.c 3. d 4. c 5. d 6. a 7.a 8.b 9.c 10. a
Explanation:
Air passes through is: Nostrils → nasal cavity →Pharynx → Larynx →Trachea → Bronchi (with cartilaginous rings) →Bronchioles (without rings) → Alveoli (air sacs). Alveoli are the seat of exchange of O2 / CO2 between lungs and blood.
If element X has 15 protons, it would also have 15 electrons.