Gender defining articles
Why doesn't duolingo include the articles la or el for Spanish OR der, die, das for German in the flash cards or on the list of words. Since this is one of the toughest skills for native English speakers, the articles should always appear on the simple word list or flash card so we can always associate them instead of guessing.
From the Coursera course, The Bilingual Brain, I learned that the reason native Spanish speakers know grammatical gender so well is that they learn the article and the noun as a unit when they are children. So I agree that Duo should include the "the."
(But I wonder how it is for Russian speakers, because there are 3 genders but no articles.)