Hahahahahahah just great!! The face of the second man who tried to take his name pretty much sums up the challenge it is to learn polish xD
From what I understand about this notion, yes, I'd say that there is. Of course mostly the clauses will be using some conjunction, but they could also be totally independent.
Well, it's one of the most basic constructions: "X is Y" can be translated as "X in Nominative + to + Y in Nominative" or "X in Nominative + a form of "być" + Y in Instrumental" - that is, if both X and Y are noun phrases. If X is a personal pronoun, only the second option works.
More info here: https://www.duolingo.com/comment/16373167
I have to disagree. In Russian, this sentence would be "Я мужчина, (а) ты женщина." Everything is in nominative.
Also, when "something is something", Polish often uses the dummy pronoun "to", which requires both nouns to take nominative.
It would be easier to teach polish people to speak english....this is a ❤❤❤❤❤❤❤ head melter
Punctuation isn't assessed on Duolingo, so either something else was wrong, or it was a bug.