In the food section I just learned "jugo" instead of the Spain-Spanish "zumo" and thus, I wonder if duolingo.com teaches strictly Mexican Spanish, or is it a mix?
It's not just Mexican. Certain words are much more commonly used throughout Latin America, and are thus preferred when it comes to teaching. "Zumo" is used practically only in Spain, whereas "jugo" is used by all Latin countries--and is recognized in Spain, too. A handful of Castillian words seem archaic or even odd to a majority of Latin American speakers, including “zumo”. Also, it makes sense to specifically avoid the word "zumo" if you're going to pronounce the "z" as an "s." Otherwise, you'd be saying "sumo," which is an entirely different word. I'm not trying to belittle Castillian Spanish, as I'm a professional Spanish linguist myself. However, a learner would do well to keep in mind that Castillian is to Spanish what British English is to English--that is, a delightful and rich form of the language, but one that is rife with odd-sounding, non-standard words as well. For example, most English speakers today don't go around the world saying LORRIES instead of TRUCKS, or BESPOKE instead of CUSTOM or TAILORED.
Hi allielovesyou ... as SkylarEC said, here you find both versions, and both will be credited as correct answer! I think this is the most valuable learning tool I've ever touched!!! And I really don't mind learning Spain-Spanish and Mexico-Spanish parallel, there is soooo much space in our brains... :-)