Question

the ____ mountains, circled in purple on the map above, stretch across western iran and are located next to the khuzestan plain

Answer 1

I think it is the Alborz mountain range. 

Answer 2

The Alborz mountains, circled in purple on the map above, stretch across western iran and are located next to the khuzestan plain.

Step-by-step explanation:

There are two large mountain ranges in Iran. One is the Alborz Range which is located from Northwest to Northeast Iran, with Iran's highest peak (Mount Damavand, at 5,671 meters above sea level) near Tehran. This mountain range, along with the Zagros mountain range, has a total length of 1,500 km.