Who led the Tonight Show Band on NBC and founded the hip-hop inspired band Buckshot LeFonque?

The gradual variations in shape, color value, and shadowing in Siqueiros's Echo of a Scream refer to

A. balance B. proportion C. gradation D. unity

What time period do we associate with classical Hollywood?

a. the late 19th century b. the period before the advent of sound c. the period from the advent of sound through World War II d. the early 21st century