Astring is composed of two violins, one viola, and a cello

A String Quartet.

A string quartet is defined as a group of four instruments or a musical combination typically based on 2 violinists, a violist, and a cellist. Hence the string Quartet is said to have 2 violins, a viola, and a cello.

a chromatic scale uses the twelve tones of the octave, while a regular scale only uses eight, or seven different notes (as the first note is played twice)