Which rock was often used to make arrowheads because its edges are very sharp?

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?

What were some of the characteristics of renaissance art?

Identify dr. linda nochlin’s contribution to art history. dr. linda nochlin contributed to the field of art history by researching and promoting the role of artists.