Answer:i think its the last one
Explanation:For their city to endure, the Inca had to find a way to keep it from sliding down the mountain. Perhaps the most visually striking features of the drainage system are the agricultural terraces. Machu Picchu includes 4.9 ha of agricultural terraces, which are held in place by stone retaining walls.
to provide protection from their enemies
Joseph Stalin was the former Prime Minister of the USSR
Joseph Stalin was from Georgia and his dad was a drunk. And Joseph Stalin was often beat by his father.
'Stalin's regime forcibly purged society of what it saw as threats to itself and its brand of communism, which included political dissidents, non-Soviet nationalists, the bourgeoisie, better-off peasants, and those of the working class who demonstrated "counter-revolutionary" sympathies."
stalin was feared because he was a brutal dictator who had dissenters exiled or killed