It's sizing someone up - it means to take their measure, to analyze them and decide what sort of person they are, how they're going to act, that sort of thing
No but someone could be allergic to sand.
no no
They are sizing you up.
you can be allergic to just about anything
It is possible for someone allergic to horses to also be allergic to camels. The allergy is most likely to the dander, and horses and camels can have similar dander.
Yes! My mother is allergic to both.
Yes, if they are allergic to an ingredient inside them.
no
yes
yes i am deathly allergic to them. i swell so big.
I don't even know what Stockholm tar is but I'm willing to bet that someone, somewhere is allergic to it. With as many people as there are in the world, someone is allergic to just about anything you can think of.