-ę eniding is for feminine (and few masculine) nouns ending with -a (Accusative)
-a ending is for masculine nouns ( most, those not ending with -a) - Genitive.
Accusative = Genitive for all masculine "animated" words (persons and animals) , and some other words - and pomidor is one of the exceptions. (I think Many vegetables and fruits are)
The problem is that Duolingo just teaches us to remember things as they are, but it doesn't explain why a word is changing according to cases...That makes it very hard to learn it the proper way in my opinion. But your comment is very clear, dziękuję bardzo!
It's exactly why Duolingo has lesson and tips on its website. I think it's really important to read them.
What is the root of pomidor, where did the word come from? It sounds like the french "pomme d'or", 'golden apple"...
Duh, it's Italian of course... The Polish probably imported the name together with the actual 'owoc'. :-)
Because tomatoes are countable. You should've written "A tomato" or "the tomato".
I'm no expert, but if you say "I eat a tomato" don't make much sense to me. But when you say "I eat tomato" it means you are able to or like to eat tomato. So you shouldn't use articles here.
I was taught that only masculine animate nouns got the -a suffix for accusative case; and that masculine inanimate nouns had no change from nominative to accusative case. Is that wrong? "Pomidora" makes it seem wrong.
That is right (well, more specifically: masculine animate nouns have Accusative identical to Genitive), but actually most natives would treat "pomidor" as grammatically animate. Yeah, Polish is illogical sometimes. See here, part 4,5: https://forum.duolingo.com/comment/28029344
"Ta kobieta je pomidor" is actually accepted, because technically it's a correct answer, but I believe it would sound weird to most natives and it seems likely you'd get corrected if you said that.