Yes
yes it is possible to fart crayons, but it might hurt
I cannot see this to be the case with modern crayons. Perhaps when they still contained toxins. YES IT IS! My friends daughter is! She has had 27 trips to the er since she started school in August. She is allergic to the dyes in all major brand of crayons. It is possible to be allergic, it isn't always the toxins. Although a few major brands still contain lead and some brands use phthalates a chemical used to make the crayon more flexible. There are no long term studies on the side effects of phthalates, but some research has shown the chemical compound has been linked to cancer (not that that should shock anyone, everything can be linked to cancer).
no
The plural form for the singular crayon is crayons!
Yes, only if you are actually allergic to collagen. It is possible to be allergic to collagen.
Yes it is possible to be allergic to algae.
No, it is not possible to be allergic to blood. Your immune system violently reacts to the allergens you are allergic to. If anyone were allergic to blood, they'd be dead by now. But it is possible to have a phobia of blood.
Yes
yes. i am allergic to the metal in the needles but the doctor does not know why.
Yes
no, are you crazy?
yes, it is possible to be allergic to anything.