Separately and in succession (3-2-3)
I believe the answer is:
one-by-one
(Other definitions for one-by-one that I've seen before include "Singly in order" , "Individually" , "Separately" , "In single file" , "Sequentially" .)
I believe the answer is:
one-by-one
(Other definitions for one-by-one that I've seen before include "Singly in order" , "Individually" , "Separately" , "In single file" , "Sequentially" .)