Buenos Aires is the capital of Argentina. The other cities are capitals of Uruguay, Chile, and Peru respectively.

Brazil is the largest country in South America by area, while the other options are significantly smaller in size.

Brasília is the official capital of Brazil, chosen for its planned design and central location. The other cities are major urban centers but not the capital.

The Amazon River is a signature geographical feature of South America and is known as the world's largest by discharge. The other rivers are located on other continents.

Santiago is the capital of Chile and serves as its primary political and economic hub. The other cities are capitals of different Latin American countries.

Portuguese is the official language of Brazil, setting it apart from most other Latin American countries that primarily speak Spanish. The other options are not the main language spoken in Brazil.

Bolivia is one of the few landlocked countries in South America, lacking a coastline. The other options have access to the ocean.

Bogotá is the capital of Colombia and the center of its political activities. The other cities are important urban centers, but they are not the capital.

The Atacama Desert in Chile is recognized as one of the driest places on Earth. The other deserts are located in Africa, Asia, and North America respectively.

La Paz is notable for its high altitude in the Andes, giving it a distinct geographical character. The other capitals are not situated at similarly high elevations.

The Atlantic Ocean borders the eastern side of South America, while the Pacific Ocean is on the western side. The other oceans are not adjacent to the continent.

Santiago is the correct capital for Chile. The other pairings mix capitals with incorrect countries, which is why correct matching is vital for geographic accuracy.

The Iguazu River is famous for the Iguazu Falls, a major natural attraction on the border between Argentina and Brazil. The other rivers do not feature such notable waterfalls in that region.

Peru boasts both the towering Andes and extensive sections of the Amazon rainforest, demonstrating remarkable ecological diversity. The other countries do not feature both landscapes prominently.

The Pantanal is recognized as the world's largest tropical wetland and is mainly situated in Brazil. The other wetlands are located in different parts of the world.

Bolivia has a unique dual-capital system with Sucre as the constitutional capital and La Paz as the administrative center. This arrangement sets it apart from other Latin American countries.

Machu Picchu is an iconic Incan archaeological site located in the Andes of Peru. It stands as a testament to the rich pre-Columbian history of the region.

Brazil is the sole predominantly Portuguese-speaking country in South America, a result of its colonial history. All other major Latin American countries primarily speak Spanish.

The Amazon rainforest's incredible biodiversity is primarily due to its warm, humid equatorial climate that supports a vast range of species. The other conditions would not foster such a rich ecosystem.

The Andes were formed as a result of the subduction of the Nazca Plate beneath the South American Plate, which caused significant mountain building. The other options describe tectonic processes unrelated to the formation of the Andes.