Final answer:
The Andes mountains were formed by an oceanic-continental convergent plate boundary.
Step-by-step explanation:
The Andes mountains were formed by an oceanic-continental convergent plate boundary.
In this type of plate boundary, an oceanic plate (denser) subducts under a continental plate (less dense), causing the formation of mountains
An example is the Andes, where the Nazca Plate is subducting beneath the South American Plate.
Learn more about Formation of mountains by oceanic-continental convergent plate boundaries