Interesting that there is no plural in this sentence but it seems that apple/S maybe inferred by "nincs" there ARE no... (or) there IS no.... Any comments? Both are allowed btw but beware with Duolingo you will only find "appleS in the SHOP" whereas "THE apple is in the STORE"
But this sentence isn't using the possessive structure, which is covered in other lessons. It makes much more sense to translate it more literally as "there are no red apples in the store", when that works perfectly well in English. We're not trying to come up with the "best" translations, we're trying to learn/teach the correspondence between English and Hungarian
That's an adjustment to make it more natural I English. Literally it says "In the store there is no red apple", which sounds weird in English because we usually use plural for that kind of sentence.
But Hungarian doesn't use plural for that kind of sentence, so we don't say "nincsenek piros almák", even though that would be the literal translation of the English words.