2. C Minor 7th Chord Tree
(Dorian / Phrygian / Aeolian / Dorian ♭2)
I managed to cram all 4 minor varieties into this C Minor 7th Chord Tree.
The difference between C-Dorian (key B♭), C-Phrygian (key A♭) & C-Aeolian (key E♭) is only the scale being played behind each chord.
In C-Phrygian the 9th is an avoid note and in both C-Phrygian and Aeolian the 13th is not available (see purple color). Apart from that, the basic chord structure is the same for all 3. As we discussed in the book, Dorian ♭2 is not very common.