Answer:
It did not rely on enslaved laborers.
This is because they did have slaves as the lowest class, but they did not rely on them to build things. The only times they relied on the slaves was when they needed extra soldiers for wars, or needed something built urgently.
Explanation:
1,2,4
Are the correct answers
Walking. Prehistoric humans came over on a land bridge between Russia and Alaska and worked their way down into south America.
