1. Major-minor
Major
minor

2. dissonance vs. consonance
Combination of tones that sounds discordant and unstable, in need of resolution.
Concordant or harmonious combination of tones that provides a sense of relaxation and stability in music.
This majestic passage is harmonious, or consonant, providing a sense of stability in the music.
Example: Brahms, Symphony No. 1, fourth movement

3. harmony (Dominant/Tonic)

4. Basso continuo

6. figured bass