Which characteristics best describe aaron douglass's painting, song of the towers?

Song of the Towers is an important piece of art for African American history since it was conceived in times of great racial problems for African Americans and is intended to represent them.  

Two of its main characteristics are:

1. The use of symbolic elements; to represent both the problems that African Americans had to face with society and jazz as a key element for expression and freedom, to mention a couple of examples.

2. Regarding aesthetics, it's mainly drawn using geometric shapes and a brown color scheme.

Symbolic and industrial  

Explanation:

This is one of the mural paintings of the Negro was done by Aaron who was artist in the period 1900 through 1979. The murals, therefore, trace the history of the American Africans through their migration from the south to the north of the US.

The mural was elaborate both in the formal aspect and its meaning. There was also a series of constricting circles and monumental prisms that occupied the center of the composition of Aaron’s writings. They provided a monumental frame for jazz.

d. direct

the exclusive possession or control of the supply or trade in a commodity or service.