It's because it says you have to choose the one with 'en', and ägg is an 'ett-word".
So there is non gramma rule which explains when we gonna use 'en' and when 'ett' ??
Do you mean ett ägg - "an egg"? It's because an orange and an egg are two different things? :)
Sometimes the question is presented as “Complete the sentence: Kvinnan äter en ____”, with ägg and apelsin as the options. So it’s not just about knowing that an egg isn’t an orange; it’s about knowing that ägg is an ett word amd so …äter en ägg can’t be correct
Swedish grammatical genders are not usually based in any kind of easily discernible logic. For the most part, it's very much a "that's just the way it is" problem.
Try either pressing down a key a little longer to see if more options pop up, or just install a Swedish keyboard.
Have you tried to DL or add a swedish keyboard? (go to your keyboard language settings on your phone)
I don't follow........ she could equally well be eating an egg or an apple!
Swedish nouns have different grammatical genders. Have a look at my info post here: https://forum.duolingo.com/comment/26420394/Answers-to-some-common-questions-on-grammar-that-beginners-have and also at the link in it which contains some gender tendencies.
"The woman eats" as translation for "Kvinnan äter" is not accepted by Duolingo, it wants it to be "the woman is eating" for no clear reason.