Melody is the succession of single tones or pitches perceived by the mind as a unity. Melody is the horizontal dimension in music, while harmony adds vertical perspective. Chords are the essential part of harmony. The harmony is the "vertical" relationship between simultaneous chords. So, harmony is the "vertical aspect" of music and melody the "horizontal".
Advantages of two-dimensional art forms, like photographs, are that they can sometimes give the illusion of being in 3D and they have distinctive elements that make them unique from 3D.
The vocalist or singer performs the song without any music in the background or instruments
