The Standard of Ur shows all of the following EXCEPT

The five possible reasons explaining why art may be created are

Suppose that you are in a room with 3 doors and a crack in the ceiling for light. that is all. the doors each have a sign on them that says what there is behind them. door #1. a pool of corrosive acid. door #2. a crocodile that hasn't eaten in 8 months. door #3. a solar "oven". a giant lens that focuses all the sunlight at the entrance of the door. you must choose a door, which door do you choose?

Which does the author mean by " nature had to kindle all the fires, for man by his own effort was unable to produce a spark