The use of different musical styles or techniques in a composition is known as

The answer is polystylism. Polystylism is the use of multiple styles or techniques in not only in music or composition also in literature, art, film, or, especially, music, and is a postmodern characteristic.  The mixture of two traditional chords sounding together is known as a polychord. 

are do fireworks on the free way is safe ?

answer michelangelo; i believe this is correct, plz check first good luck;