Scale

Natural minor (Aeolian) is the “darker / melancholic” counterpart to major. It’s the relative minor of a major key (same notes, different tonic), which is why modulating between relative major/minor feels so natural. Common genres: rock, pop ballads, classical, cinematic, indie. Usage: great for i–bVII–bVI progressions (a classic minor-key sound), and for melodies that lean on the b3, b6, and b7. Harmonically it lacks a strong leading tone (7→1), so cadences can feel modal unless you introduce harmonic/melodic minor.

Exercise — Parallel motion in thirds

Hands a third apart: LH on the tonic, RH on the 3rd degree of the scale. Hands stay close, keep the thirds even. Two hands. Scales in parallel thirds are a common enough thing for intermediate to advanced technical exercise. Fingers crowding each other is what makes it challenging, but it is do-able. Each hand plays the scale as it ordinarily would, just separated by a third. The fingering is on the notation, just take it slowly until you’re able to do it, then gradually increase speed. There’s really no trick to it beyond that.