How does the cause-and-effect structure support the author's viewpoint that the United States has a false sense of isolation?

Hi. You did not enter the text to which this question refers, which makes it impossible for it to be answered. However, I will try to help you as best I can.

A cause and effect structure is the one used in a text that shows how an element is capable of causing the existence of another element, that is, it shows what was the cause of any effect. To answer your question, you need to read the text it is related to and identify when this kind of structure is established. This moment must present the false sense of isolation as a cause or an effect, so that you can interpret it and answer your question.

either a donut or a sphere or a pancake or a flat sphere. it depends on where the vertical line is.

if the line goes through the center of the circle and is perpendicular to a diameter containing the center, then you get a flat circle.

if the line and the diameter of a the circle meet in the center of the diameter and at an angle, you get a pancake.

if the line is on the circumference of the circle and is at right angles   to the circle you get a ring.

if the line contains the diameter, you get a sphere.

the the line is parallel to the diameter and touches the circumference, you get a donut.