1. Energy transfer is the movement of energy from one location to another. For example, when electricity moves from a wall plug, through a charger, to a battery.
2. Insulation helps to prevent that transfer of heat. Many different materials are used for insulation. Engineers often use fiberglass, wool, cotton, paper (wood cellulose), straw and various types of foams to insulate buildings. A layer of trapped air can serve as insulation, too!
3. I'm not sure. Sorry