The correct option is (a).
Explanation
South America is the fourth largest continent in the world, situated primarily in the Southern Hemisphere and characterized by distinct physical features such as the Andes Mountains and the Amazon Basin.Statement 1 is Correct: The Equator passes through the northern part of the continent (crossing Ecuador, Colombia, and Brazil). Consequently, the major portion of South America lies in the Southern Hemisphere.
Statement 2 is Incorrect: The mountain range that runs through the length of South America along its western coast is the Andes. The Rocky Mountains (Rockies) are located in North America.
Statement 3 is Incorrect: The Amazon is the primary river system of South America and is the largest river by discharge volume. The Nile, traditionally considered the longest river in the world, is located in Africa.
Key Takeaway: South America is defined by the Andes Mountains in the west and the Amazon River in the north-central region, with the majority of its landmass situated south of the Equator.