How can a melodic riff be added above a chord sequence?

Music

A sequence of notes - the main tune of a song.

When you play two or more notes at the same time.

A riff is a short repeated phrase in popular music.

A riff is a type of sample used in EDM music.

A riff is the chord used to harmonise a melody.

Who is considered to be the father of harmony?

Everyone singing / playing the same pitch at the same time

Two or more pitches being played at the same time

A short repeated phrase in popular music.

A bass line using the 1st pitch from the chords

A bass line using the 3rds from the chords

A bass line using the 5ths from the chords

What would a root note bass line be in this chord sequence? Dm, Am, C, F

How can you add interest to a root note bass line?

How could you change the melodic shape of a bass line?