Why does the professor mention wheels and spheres？A．To illustrate how movement can be expr

Why does the professor mention wheels and spheres？

A．To illustrate how movement can be expressed in a piece of art

B．To demonstrate that objects are more important than colors in a piece of art

C．To give an example of objects that have symbolic significance

D．To explain why some objects rarely appear in works of art

此题为多项选择题。请帮忙给出正确答案和分析，谢谢！