Yo WaSsuPp!!  ^v0!!
                                    please help bio 3 question 
I gotchu!! ^v^
The answer is:
                                     "aa"
 If both letters are lowercase then that means the trait is recessive, and since cystic fibrosis is recessive this is your answer.
I apologize if i'm wrong // Your're welcome if i'm correct
((-Side Note-)): If you don't mind can you pls mark my answer branliest?
                   Thank you and i hope you have a great day! ^v^