"Are you men or boys?"
Translation:Seid ihr Männer oder Jungen?
because "dich" is an accusative personal singular pronoun in the second person, or "du" ("you" singular informal)-- Try to learn the pronouns in German and the verb "sein' well because you will need them a lot for the very basic. Your alternatives in this phrase are (1) Seid ihr (informal plural "you",) or (2) Sind Sie (plural formal "you".) -- (Männer und Jungen are obviously a plural.) I find this Duolingo link useful: https://www.duolingo.com/comment/19781880/When-would-I-use-dich-dein-euch-du-and-eure
"Männer" (must have the dots over the "ä") and Jungen are both nouns which must capitalized, like all German nouns. You can translate "you" as either informal plural "ihr" or formal "Sie", but the form of the verb is different for each of those two pronouns. If you use "Sie", the correct form of the verb in this sentence is "sind"; if you use "ihr", the correct form of the verb is "seid". You cannot use "Sie" with "seid" or "ihr" with "sind".
Word order: in German, as in English, one usually starts a question, with either a question word - who, what, how, when, and so on - or with the verb. If the verb is more than one word long, the sentence generally starts with the so-called "helping verb", the one that doesn't carry the actual verb meaning, followed by the subject: DOES she know? ARE we leaving now? COULD Mary bring back something for supper? WILL the teacher give a test today? So your sentence should be either like the given answer, "Seid ihr Männer oder Jungen?" or (just as correct) "Sind Sie Männer oder Jungen?"