"¿Por qué Europa necesita una Constitución?"
Translation:Why does Europe need a Constitution?
In (grammatically correct) questions, the subject cannot begin the question nor can it immediately follow the question word (e.g. who, where, what, when, why, how), so we add an auxiliary verb between the question word and the subject or in yes/no questions, we add the auxiliary verb to the beginning of the question.
The auxiliary (helping) verb we use is "do":
Why does Europe need a constitution?, Does he understand the question?
Note that the verbs need and understand are not conjugated. In questions with 'do', only 'do' is conjugated (do I, do you, does he, did I, did you, did he...), the verbs are not.
"Why Europe needs a constitution" is a phrase, not a question, so it wouldn't be a correct translation in this case.
Duolingo needs to craft more Spanish questions with the NORMAL verb–subject word order. The subject–verb order in questions is less common. Also, there's no reason whatsoever to capitalize constitución here. It's not a proper name; it's a generic noun.
No. The name "constitution" was deliberately removed from the EU Treaty of Lisbon.
The EU has a framework document that can be considerd a constitution.
Well, the EU does not equal the continent (how can the Duolingo team dare marginalizing the Swiss?! They have to be taught some tolerance! ;)) not have even anything resembling that and the EU wanted the introduce a document with that name, it was met with a lot of opposition, so they changed some details, gave it a different name (Lisbon Treaty) and pushed it through anyway (I mean, the Irish rejected the Lisbon Treaty in a referendum but they simply made some minor changes and held another referendum to make it pass...but maybe let's not go too deep into politics :) ).