the moutains on the western edge of south america are the:

a. seirra madre
b. rocky mountains
c. andes
d. western highlands

Right.

The mountains on the western edge of South America are called the Andes. To find the answer, you can use various methods. One way is to consult a reliable geographic reference, such as an atlas or an online map. Another way is to search for information about the major mountain ranges in South America.