There are two types of tonalities (or keys) in tonal music: major and minor. The accidentals--sharps and flats--most used in keys are standard so they are often written as key signatures to avoid cluttering the music score with too many accidental signs.
D. Teresa Carreno She was a renowned Venezuelan pianist, singer, conductor, and composer. She composed short piano pieces by the age of 6 and debuted by the age of 8.