2.) Show an example of a great circle.

 

According to the site listed below, a great circle is defined as "A circle defined by the intersection of the surface of the Earth and any plane that passes through the center of the Earth." The site also adds that "On the idealized surface of the Earth, the shortest distane between two points lies along a great circle." The Equator, the Prime Meridian, and all other lines of latitude and longitude are considered great circles.

The information was found at the following site:

http://www.its.bldrdoc.gov/fs-1037/dir-017/_2490.htm

The picture was found at the following site:

http://www.thinkgeek.com/images/products/other/great-circle-diagram.gif