I think it should be accepted because it's technically correct, even though you wouldn't say it like that in Russian. I suppose that "Her cat is eating everything!" would be something like "Её кошка поедает всё!" but even that's a bit awkward and personally I would use the future tense here, as in "Her cat will eat everything" – "Её кошка всё съест".
"her cat is eating everything" not accepted 4 Feb 2018, Reported.
Hover hints for ест: "eats/is eating/eating".
Also, no Russian continuous tense has been taught.
Also, English is very flexible. The choice between "eats/is eating" often has more to do with sonority of the sentence rather than grammar, unless you specifically intend to mean that the cat is eating everything **at this moment/right now" - and in that case, if in writing, you either write "right now" or use an exclamation point. If speaking, you add oral empahsis - "The cat is eating EVERYTHING!"
"Его" и "Её" are somewhat close in sound, so your trouble discerning between the two makes sense. "Его" sounds more like "ee-voh" in English, whereas "Её" sounds a lot more like "ee-yo". Hope that clarifies it for you a little bit, I know sometimes Duolingo's recordings can sound a little confusing / muddled from what you'd think it sounds like.
Why is it not "Кошка она ест всё"? I thought in the genitive case (to express belonging) one uses the order possession-possessor order.
"Кошка Димы" - Dima's cat
"Рюкзак Анны" - Аnna's backpack
Is it because the possessive pronoun "её" both obeys different rules and is more common in Russian?
Can someone please tell me why why why there are so many different forms of you, she, their, etc. Uuuhhggg is so hard to remember when to use which.