#12: "The amount of oil spilled was more than the Exxon Valdez incident and the toxicity considered higher, because of the higher water temperatures." (Wikipedia)
99% of non-Spanish quiz takers would not even know why they'd have to enter "invencible", but I do see the problem. This is one of the cases that English "misappropriates" a foreign word (also happens to and in my own language). I changed the wording so that it makes more sense to Spanish speakers.