"The mobile phone has a camera."
Translation:Το κινητό τηλέφωνο έχει κάμερα.
Isn't κινητό already 'mobile phone'? I have never heard of a 'κινητό τηλέφωνο'. But using only κινητό was marked wrong...
Both "κινητό" "κινητό τηλέφωνο" are accepted answers. If your sentence was rejected that wasn't the reason. When Duoling rejects a sentence it tells you the reason. But only you can ssee that. We cannot.
Next time that happens be sure to report it as: "My sentence should be accepted." then Duolingo can check for any irregularities.