Vivaldi - Concerto in D minor- Tonality

Question 1

What key is the piece in?

Answer 1

D minor, most music remains in the tonic key

Question 2

Which keys do the music briefly modulate to?

Answer 2

G minor (subdominant) and A minor ( dominant)

Question 3

The music uses functional tonality. What is this?

Answer 3

where key relationships are built on a

carefully controlled process of using related keys