piano scale
D natural minor
D1E2F♭3G4A5B♭♭6C♭7
The major scale started from its sixth degree: same seven notes, a different centre of gravity.
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
DWEHFWGWAHB♭WCWD
What is true of it
D natural minor is D, E, F, G, A, B♭ and C, and back to D.
Its steps are W – H – W – W – H – W – W, where W is a whole step and H a half.
On the same tonic, D harmonic minor differs from it by exactly one note.
Chords made only of these notes
CmajorC7dominant seventhDmminorDm7minor seventhEdimdiminishedEm7♭5half-diminished seventhFmajorFmaj7major seventh
Found by testing every chord in the catalogue against these 7 sounds, not chosen.