Why do we have limited knowledge of pre-columbian art in americans

What would be some of the drawbacks of using a specific dramatic structure such as freytag's pyramid?

In art, what does the term, “form” mean? a. the pleasing arrangement of parts or objects, along with the characteristics shared between the objects. b. any three dimensional geometric shape. it can also refer to the visible elements of a piece. c. the sense of balance achieved by placing objects or forms that are different on either side of a central line. d. the relationship, either of time or space between recurring elements of a composition.

What argument does the author make in this excerpt from cannibals all! or, slaves without masters, written by george fitzhugh in 1857?