The correct answer is option 2, Pampas. The temperate grasslands in South America are known as Pampas.

Option 1, Prairies, is incorrect as Prairies refer to temperate grasslands found in North America.

Option 3, Downs, is also incorrect as Downs are grassy, hilly areas found in Southern England and Australia.

Option 4, Steppes, is incorrect as Steppes refer to the vast, dry grasslands found in regions of Eastern Europe and Central Asia.

Therefore, the correct term for the temperate grasslands in South America is Pampas. Pampas are extensive plains characterized by fertile soil and rich grasslands, which are important for agriculture and grazing.