Convection, because it is the process of heat transfer from one location to the next by the movement of fluids. The moving fluid carries energy within it.
The sun is the primary source of light. Other artificial sources are light bulb, torch light and some others. Thats all i can think of.
because the building are weaker and they are most likley to fall
Because the sound waves are being observed by the people that are there and it is not empty as in an empty place the sound waves will come back to you.