"A sandwich is bread, cheese and meat."
Translation:Kanapka to chleb, ser i mięso.
Is the oxford comma a thing in written polish? This isnt necessarily about this question in specifically, but this is the first translation I've come across with listing things in a sentance. I used it in my answer, and it was accepted. However, I've noticed that I can forgo punctuation entirely and Duolingo will still accept my answers so I am still unsure about it.
Duolingo doesn't assess punctuation, so you're right to be unsure, the fact that it was accepted doesn't really say anything.
No, unless I am unaware of something, Oxford comma isn't a thing here, it would be wrong to put a comma before "i".
The situations which call for a comma before "i" are when you add an apposition and when "i" is repeated in a sentence.