According to my dictionary, mlo and chakula have a lot of overlap in meaning but chakula looks like a much more common word. It appears in all kinds of phrases throughout the dictionary. If you get it again and it doesn't accept mlo, report it.
Na asante kwa kunifundisha neno jipya!
"meal" seems more formal; like put together - chakula (from "kitu cha kula" "something to eat") is the more coomon, yes, BenUserName :)
once again - the use of articles is so messed up in this program. In english this could equally be you have not cooked food as well as you have not cooked the food.
Ya it is hurting my brain trying to figure out when they have a definite or indefinite article or none in the answer as it seems random and often not the way I would say it in English.
I can't get past this level because it so inconsistently requires "all" for you all or does not require "all" for you all!