How were the Inca able to maintain a population of over 1 million people in the terrain of the Andes Mountains?

A) They became expert navigators and controlled the maritime trade.

B) They became skilled hunter-gatherers of local wildlife and vegetation.

C) They relied on the relief efforts of the Spanish conquistadors to survive in the Andes.

D) They developed terraced farming, allowing them to grow food on the mountain
sides.