1.   How could so many dinosaurs and other animals survive in an arid expanse of sand?

2.   More than the setting has changed, from a tropical island to the arid expanse of the Outback.

3.   What little grass and other vegetation is usually available in the arid expanse has been all but wiped out.

4.   Zander designed culverts to channel the water above the dam into streams that irrigated about eight acres of the arroyo, turning arid expanses into marshland.