I think that both English phrases are correct in their own context. For example, if you were speaking generally about meat, you would say that 'fresh meat is delicious', but here it sounds more like you're describing the meat as something in a list, so you might say 'the yogurt is tasty, the bread is soft, and the fresh meat is delicious'. Just saying 'fresh meat is delicious' (without the ” the”) wouldn't sound right in the above example.
Another example could be a waiter asking you how your meal is. You may answer that 'the fresh meat is delicious', and you'd mean that the fresh meat you are eating is delicious, whereas if you answered with just 'fresh meat is delicious' it could be taken as a complaint that while meat is delicious when fresh, the meat you are currently eating isn't delicious because it isn't fresh! :)
They mean different things though. "Fresh meat is delicious" means that you like eating fresh meat in general, whereas you would say "The fresh meat is delicious" if you were talking about specific meat. So for example if you were complimenting a meal, or saying "The fresh meat is delicious [but the other meat that's rotten isn't]".
On Greek words of more than one sýllable, the áccent mark is placed on the áccented sýllable.
So if you know how to pronoúnce Greek, it’s óbvious where the áccent mark goes.
Ótherwise, just learn the posítion of the áccent mark as part of the spélling of the word... and remémber that the posítion of the áccent may change when the word chánges (as with Énglish phótograph, photógraphy, photográphic).
What did the exercise ask you to do? Type what you hear or translate in English? We don't know why an identical phrase to the given sentence in the exercise may have been rejected.
In such cases, you can report this as a bug directly to Duolingo here https://support.duolingo.com/hc/en-us/requests/new.
There are more than one spaces between φρέσκο and κρέας in your answer. This bug has caused answers to be rejected before. I see now that's also the problem with gerda30's answer. If you copy and paste from your comment to a text editor and move the cursor back and forth between those two words with the arrow keys, you'll see there are two extra spaces. If you use that text in the Find in page browser function, you'll also see it only matches your answer and gerda30's answer, not the exercise. I don't know how it is caused.