How has physical geography determined settlement patterns in south America?

Physical geography has significantly influenced settlement patterns in South America by shaping where populations can thrive. The Andes mountain range creates barriers to movement and accessibility, leading to densely populated areas in valleys and plateaus. Conversely, the Amazon rainforest's dense vegetation and challenging terrain limit settlement, resulting in lower population densities. Additionally, river systems like the Amazon and Paraná have facilitated trade and agriculture, encouraging settlements along their banks.