The inconsistency of Duolingo gets frustrating sometimes. If yoou translate this as "Ka'iulanu eats the large kalo," it's incorrect. First of all, kalo is a Hawaiian word; taro is a Tahitian word. But then if you translate "pua'a kalua" as "baked pig" it ewrong; they want youi to keep "kalua" in your answer! Then why can't I keep kalo in my answer?
I think the inconsistency is in English. The English term for "pua‘a kalua" is "kalua pig" (borrowed from Hawaiian), but the English word for "kalo" is "taro" (borrowed from ... Tahitian? Maori?).
At least that's the case in my dialect, but I spent four teenage years on O‘ahu, so my dialect of English is probably not typical of mainlanders.