xwater usage in arid regions - phoenix, az. the problem 6 placemarks highlight two distinctly different areas near phoenix, az...one natural to the region and one artificially supported by irrigation. which of the following is correct? a. problem 6a - lush, green golf course; problem 6b - arid desert with dry washes b. problem 6a - arid desert with dry washes; problem 6b - lush, green golf course