I hate "false friends"...
owoce, right? :)
Yes, of course "owoce" :)
Is not the literal translation of "на" "on". If so why does the correct answer use "for" and not accept "with" or "as" or "in". Using the work "for" makes it sound like you will ONLY have vegetables as your entire meal. What are you : Vegetarian?
Do plural nouns have accusative forms?
Yes. they have. But some forms are the same as nominative. You can look for patterns here: https://www.duolingo.com/comment/8868469