"What is orange?"
When tpdoes one use narancs and when does one use narancssarga? Both see to be colours
Come on, this is a weird sentence in English, and can be interpreted several ways. I, for one, read it as "what is the color orange" (such as, "please describe this color to me"). It could also mean "what is it that is orange in color", which seems to be how Duo wants it translated. I would suggest just avoiding such ambiguous questions if possible.