Triads and Seventh Chords

In D Minor, what roman numeral indicates raised Seventh leading tone building half step below Tonoic?

When harmonizing 'Twinkle Twinkle Little Star' starting with tonic triad in C Major, what diatonically correct roman numeral should follow initial I to create strong melodic cadence at end?

Which diatonic chord quality does iii represent in E minor?

In a minor key, which diatonic chord is most commonly altered to create a leading-tone when harmonizing the penultimate note of a melody?

When modulating from C major to G major within a piece of music, which secondary dominant would typically precede the introduction of D major, the V/V in G major?

What function does the ii chord serve in a major key progression?

Which Roman numeral represents the dominant chord in a minor key?

In a melody composed in the key of C major, which chord would best harmonize a non-chord tone of A that resolves down to G?

In C Major, what is the quality of chord built on supertonic noted by roman numeral ii?

In a minor key, which diatonic chord typically substitutes for V to create a less resolved cadence?