Which will cause allergies if you inhale them, eat them, or touch them? antihistamines bacteria allergens antibodies

The only thing here that is capable of causing allergies is an allergen. Hence the name, it stimulates an immune response to a harmless antigen.

An antihistamine is a substance the prevents the swelling of certain areas of the body due to an increase in histamine production in that area.

An antibody is a type of white blood cell that fights disease.

Bacteria are microscopic organisms that are capable of doing a variety of different things, none of which are pertinent to your question.

I hope I helped!

If you'd like me to elaborate on my response, then just leave a comment down below and I'll gladly do so. :)

(I'll also help you with other topics/questions, if needed).