The correct answer is by using the antagonist.
The antagonist is a molecule that blocks a biological response by binding to the receptor. So, you add antagonists to the receptors you want to determine and see which antagonist blocked the response. By blocking the specific response you can get the answer what receptor it was.
I'm almost certain that the answer would be X and Y
Hoped this helped!
The combination of citrus food in the diet may help Jared in creasing the absorption of iron by his intestine. The fruits and vegetables rich in Vitamin C and the Ascorbic acid such as lemon, oranges etc., may be used. Further, beta-carotene rich sources like carrots, apricots, beans, spinach also will also help him.
The answer is: subduction zones.