Assembly and Rigging

I need 5000 words exact. 1. Explain the difference between center of pressure of an airfoil and center of gravity and which one is usually ahead of the other? 2. What is the aspect ratio of a wing? 3. Explain MAC (Mean Aerodynamic Chord)? 4. Explain when the forces of lift, drag, weight, and thrust are balanced and in what condition of flight?