JAMB Biology 1980 Question 46

Oxygen from the atmosphere reaches the mammalian bloodstream through one of the paths indicated below. Indicate the correct path. a= mouth, b= trachea, c= bronchiole, d=nostril, e= bronchus, f = alveoli

1. A.a → b → e → f → d
2. B.b → d → f → e → c
3. C.d → b → e → c → f
4. D.b → a → f → e → c
5. E.f → e → c → d → c.