Answer:
The most important forms from the Classical period are the string quartet, opera (which includes the opera buffa and opera seria genres), trio sonata, symphony, and solo concertos written for a variety of different instruments. While each of these musical forms are separate and unique, they each have the same three key characteristics in common:
Simplicity
Classical period music borrowed melodies from folk music and could be arranged to create new variations with changes in tonality, tempo, and dynamics. While this trend got its start during the Classical period, it would continue to be used, and indeed expanded, during the Romantic period that followed behind the Classical era.
Classicism
Each of the musical forms that became standard during the Classical period embraced order, simplicity, strength, and a celebration of humanity – all of which are perfectly aligned with reverence, respect, and love for Classical Greece.
Accessibility
This, in turn, helped to make Classical music significantly more open, popular, and generally egalitarian than Baroque music, which was most often performed as chamber music exclusively for upper-class listeners.
