Answer :

It Uses Diatonic Scale

Explanation :

In music theory, a diatonic scale is any heptatonic scale that includes five whole steps and two half steps in each octave, in which the two half steps are separated from each other by either two or three whole steps, depending on their position in the scale

Also There are 7 Diatonic Modes :

1. Lonian

2. Dorian

3. Prhygian

4. Lydian

5. Aeolian

6. Locrian

Consists Of Several Scales :

do (or doh in tonic sol-fa),[2] re, mi, fa, so(l), la, and si or (ti)

Sorry if it was unhelpful or Wrong Answer, Anyways Cheers! :D