What stretches between the arctic ocean
and the gulf of mexico?

I'm taking a wild guess, but the Northern Artic Circle? (also known as latitude 66.5°N)

Explanation:

You can see from this map that it cuts between the two oceans.

(ok btw sometimes the degrees for the Artic circle are different in textbooks, but I learned that both artic circles were located at 66.5)

christianity is the most common religion in poland among the polish.

answer conditional instability;