Looking at this chart:
. . . it is not hard to see the minor thirds (remembering always that a minor third is made of a whole step plus a half step).
RE to FA
. . . is a m3
LA to DO
. . . is a m3
MI to SOL
. . . is a m3
DO to RE would
NOT
be a m3
FA to LA would
NOT
be a m3
DO to MI would
NOT
be a m3
