Explain the concept of "the axis" and the principle of "crossing the line."  Make sure to describe:a.          both the "right" and "wrong" of the concept of respecting the axis b.          why the concept developed and why the principle is usec.          why a director would want to respect the axis or to "cross the line"

What will be an ideal response?

See Chapter 1, "Understanding the Axis."  For example: "Imagine there was a line drawn between the two armies. In cinema, this is called the axis. To preserve continuity, the camera must always be set up on one side of the axis. Otherwise, there will be a change of screen direction that can be confusing and cause the sequence to seem jumbled or odd."
See also Figures 1-21, a, b, c 
"The Axis" developed in order to create smooth continuity in editing and make cuts seem invisible to the viewer.
A director would follow this rule to create a feeling of smooth continuity.  To explain "crossing the line," as stated in Chapter 1: "On the other hand, many directors play around with space to compel the viewer to look at the scene or the space in a variety of ways or from a confusing viewpoint. Many action movies of the twenty-first century are deliberately disorienting and cross the line during fights and chase sequences."