Duolingo should be more careful with the distinction between fantastical sentences and uncanny valley sentences.
"The duck is my grandfather" is a fantastical sentence that is memorable because it is recognizably strange, even to a beginner.
"The minute is precise" and "He opens the outlet" are uncanny valley sentences. For anyone not already fluent in both the source and the target language, they can't be sure if they're learning real-world usage or fantasy usage.
(The third type of sentence would be the realist sentence, like "Tomorrow is Tuesday", which, even if it's syntactically novel (a beginner might be confused at "terça") is still obviously useful in the real world).
The more uncanny valley sentences a language course has, learners can end up having less confidence in the strange but realist sentences, and wind up learning less well than they might otherwise do.
"the minute is necessary" is not accepted? Since "precisar" means to need, I thought preciso could be necessary. I am a native spanish speaker and we have the word "preciso" and "precisar" as well, both having similar meaning. Preciso also means accurate, exact... but I think in this case "precise" should not be accepted over "necessary". idk though. Sometimes I hate making mistakes here cause the duolingo logic seems a bit off.