16. Solids cannot transport heat through convection. Because solids are stuck in place so they can't flow and since they can't flow, there is no convection.
17. It is because the metal conducts heat faster that it feels colder than the wood, which conducted heat slower. In other words metals are good conductors of heat. It takes away your body heat as you touch it and which makes your body temperature to drop, therefore you feel the coldness when you touch a piece of metal.