Actually in English this would more likely be You (pl) are human (pl). I figured Duo would want the literal translation humans but I put down the collective noun human just to see what would happen.
I'm curious as to what human as a collective noun would be. EG: You are all human.
The word humans with an s is not really an acceptable english word because the word human encompasses all mankind and is therefore already plural. It is one of those words that means singular and plural with the same spelling. Howerver.... if you have 3 people and a dog and a cat you could say there are 2 animals and 3 human beings, placing the s on beings.
"You are human" may sound more natural, but it's still incorrect, since "human" needs to be plural as it is in the French sentence. Keep in mind there is a difference between "human" as an adjective, and "humans" as a noun.
Also, I agree that "human beings" should be accepted.
interesting....http://www.learnersdictionary.com/search/human it's not likely that i will ever need to use those words in that order,,, As an English person learning French, i just think it's bad English grammer in this case to use humans in the plural. Maybe in the French language it is acceptable. Perhaps this program will also improve my English grammer and vocabulary. !
As it should be, since in English you are some humans is so unusual a construction, any reader would be puzzled as to what exactly was meant by such a statement. In French articles are required because they convey necessary information about the noun they modify, number, gender etc. In English, where articles are not required sometimes including one changes the apparent meaning of the statement.