The correct answers from the choices are:
a. Reduce inflammation locally
b. Antagonize H1 receptors
c. May be administered orally
<span>d. Are systemically distributed
</span><span>Antihistamines are drugs that are H1 antagonists or blockers, may be administered orally, are distributed systemically, and do not directly reduce nasal congestion.</span>
1. 1 M , 2 M , 1 M
2. 10 mol , 0.1 mol , 0.5 mol
3. 0.5 L , 6.6 L , 5/21 L
M = mol/L
