I disagree, but even giving the benefit of the doubt, if it's TECHNICALLY right, it's still a strange way to put it, in the opinion of multiple native speakers. Maybe I'm crazy but I'd think that Duolingo would want to minimize unnatural/awkward/questionable grammar and syntax in their language courses.
I'm a native speaker as well, and while I agree that it probably isn't the best way to put it, if I can say "science studies the natural world" (and I definitely can) then I can also say "medicine studies diseases." As for minimizing awkward grammar and syntax, I very much agree. But translation isn't always as simple as we would like it to be. Looking at the English translation available for this sentence now, I don't think it's exactly ideal either. Sometimes (in my experience at least) a sentence that is a little wonky in English helps me to remember differences in grammar in my target language and ultimately improves my speaking ability. Just a thought.
@Ser229339 You are right. The correct Romanian pronunciation here: https://drive.google.com/file/d/1TrX1aHv_Vahggal5kHmQiX7sQxByRLW2/view?usp=drivesdk
We deal here with an interpretation and not a translation.
The translation of the English sentence "Medicine is the study of diseases" has this mot-a-mot Romanian translation: "Medicina (as a science) este studiul bolilor." I ignore here the truth value of the sentence.
This interpretation "Medicina studiază bolile" is a correct sentence in the Romanian language, and can be used to explain what is the Medicine to a kid, but it is not the right translation.