Final answer:
Modernism in American design in the first half of the 20th century was characterized by the use of industrial materials and simplified forms, along with sans-serif typography. However, it did not include the use of excessive decoration, handcrafting, and historical styles.
Step-by-step explanation:
Modernism in American design in the first half of the 20th century was characterized by several ideas and elements. These included the use of industrial materials, technologies, and techniques to create bold structural frames with clean lines and plain or shiny surfaces. Modernism also emphasized simplified forms and sans-serif typography. However, one element that did not characterize Modernism in American design was the use of excessive decoration, handcrafting, and historical styles.