The cost of a human life
The evil nature of men towards each other
The search for children who had been sold
The quick passage of time in the life of a child
Protecting the interests of native-born or established inhabitants against those of immigrants
Answer:
I'd probably say monolithic domes for 4. They learned how to make a really strong large dome structure that could support a lot of its own weight. I'm not sure for 3 but maybe arches and columns.
Explanation:
