I was marked incorrect for saying "why eat food?" (I thought this was an impersonal plural) Just got this as a 'Correct" response:
You used the wrong word. Why do I eat food?
I'm confused:- (as well as not being autotrophic).
HMM THATS A TOUGH QUESTION Its not like we need to eat food to survive or anything....
There is no "you" (or any other pronoun) in this sentence: I think it's what was described in the Tips & Notes as an Impersonal Plural. So the import of the question is "why is food eaten?" ie what is the general purpose of consuming food? It's not directed at a specific person, or specific act of eating, so although it's tricky to translate this sort of expression it English, I think the official translation they've given here is the closest English idiom in general use.