"Boys drink water."
The question didn't have a definite article but the answer requires one? Weird.
In Italian you still need to use the definite article when making generalisations
I'm Spanish native speaker and it's the same in Spanish (both are latin languages and gramatically very similar): all nouns require the article when making a sentence, no matter if there's an article in the original English sentence (I can think of only very few exceptions).
In portuguese if you say "meninos bebem água" (boys drink water) it's a valid sentence. It means the same it's meant in english, which is, boys, in general, drink water.
I am learning all the Euro languages it has to offer on duolingo, and it started to confuse me after a while... but it's fun, considering it's a new way to explore my brain potential...