Answer:
The correct answer is : They reduce histamine in the blood by binding to and destroying it.
Step-by-step explanation:
Antihistamines are type of drugs that inhibits release of histamine by binding to histamine receptors and suppress the transduction pathways of histamine.
They blocks the enzymes from transforming histidine into histamine and reduce cell response by blocking histamine-induced cascade signal transduction. These are use to treat allergies, congestion, hay fever and other allergy responses.
Thus, the correct answer is : They reduce histamine in the blood by binding to and destroying it.