Question

If you were flying an airplane, balloon, or helicopter, why would you need to understand three dimensions to navigate safely

Answer 1

because not only is you position over the surface of the Earht important but your altitude as well. Therefore it would take 3 dimensions to describe your location.

Answer 2

x, y, z axis. because life is in 3D. We are all familiar with the x and y axis, z axis if i remember would be the axis that comes out vertically up.