1. These are formed by division of trachea.   6   1   10   3   Hint Half-n-half Clue   2. Larger dust particles in the inhaled air are trapped in the mucus and hair found here.   14   10   1   9   Half-n-half Clue   3. It secretes saliva.   9   7   3   5   Half-n-half Clue   4. Exchange of gases occurs here.   2   1   7   16   Half-n-half Clue   5. It is a muscular tube containing semicircular rings of cartilages.   11   2   3   5   Half-n-half Clue   6. It pumps blood to various parts of the body.   7   13   8   10   Half-n-half Clue   7. Food is mixed with saliva here.   10   15   13   2   Half-n-half Clue