paragraph: You approach the door of a friend. What is the first thing you do? Of course, you wipe your feet. You are a thoughtful visitor. Fortunately, there is a piece of carpet to wipe your shoes. Too bad your caring comes at a price. You now reach out to touch the brass knocker on the door. A spark appears between you and the door. You feel an electric shock. Why do you think this happened? Where did the electricity come from?This was a discharge of static electricity. Has this ever happened to you? Why do you think you felt a shock? What causes the electric charge to form? Lightning is created in much the same way. Both are caused by the build-up of electric charges. This is also the same reason electric current flows through cables and wires. 
question: What is the reason electric current flows through cables and wires?
answer: Because of the shock and current passed