The nearest we have to the original is in koine Greek, and it would be unusual to have only one correct translation into Italian -or English. As the Lord's Prayer was almost certainly given in Aramaic, with a very different grammatical structure, and no surviving textual evidence, can we pontificate about our version? For my take, I agree with PhilipNikolayev's more recent comment.
When doing lessons on Duo it's always best to keep to the wording given. Duo has a teaching procedure which should be adhered to. And in any case the robot is not programmed to recognize every possible expression. Here's a good site with lots of info on Duo: http://duolingo.wikia.com/wiki/Duolingo_Wiki#Getting_Help
Yes there is. "quotidiano" is an adjective while "quotidianamente" is an adverb. "Cucino quotidianamente" / I cook daily (every day)
note: "quotidiano" can also be a noun meaning "daily newspaper" (Legge quotidiani. / He reads newspapers.)
Publications can be referred to by their periodicity; a newspaper can be quotidiano (daily), a magazine can be settimanale (weekly), quindicinale (out every 15 days) or mensile (monthly). (by f.formica)
"Daily" implies something that has a regular occurrence, whereas "every day" just answers the question of how often something happens, and "everyday" describes something that is ordinary. For instance -
daily bread - bread you receive regularly every day every day bread - not something you'd say in english everyday bread - ordinary boring bread, nothing fancy
Hope this makes sense :)