Final answer:
The Spanish and Portuguese colonized South America primarily for its rich natural resources, including precious metals and lucrative plantation crops, as well as for economic profits through the exportation of goods like rubber and brazilwood.
Step-by-step explanation:
The Spanish and Portuguese established colonies in South America because South America had valuable raw materials such as silver, and gold, and agricultural products like sugar and coffee. South America also produced lots of export goods, including Brazilwood, rubber, and plantation crops, which were significant for the colonial economies of Spain and Portugal. These resources were exported primarily to Europe, fostering immense wealth for the colonizing nations and firmly inscribing South America within a global trade network.