Mountain system (5)
'mountain system' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for andes that I've seen before include "Danes seen in mountains" , "World's longest mountain range" , "A geographical feature" , "Mounts" , "South American mountain chain" .)
(Other definitions for urals that I've seen before include "Mountains on the boundary between Europe and Asia" , "Mountains of Western Russia" , "Mountains of west-central Russia" , "Russian mountain range" , "mountain area" .)