Answer:
Rhythm
The organization of music in time. Also closely related to meter.
Texture
The density (thickness or thinness) of layers of sounds, melodies, and rhythms in a piece: e.g., a complex orchestral composition will have more possibilities for dense textures than a song accompanied only by guitar or piano.
Most common types of texture:
Monophony: A single layer of sound; e.g.. a solo voice
Homophony: A melody with an accompaniment; e.g., a lead singer and a band; a singer and a guitar or piano accompaniment; etc.
Polyphony: Two or more independent voices; e.g., a round or fugue
Structure or Form
The sections or movements of a piece; i.e. verse and refrain, sonata form, ABA, Rondo (ABACADA), theme, and variations.
