three factors that helped Salva survive

Salva was resilient. He kept in survival mode and was able to suffer hardships without giving up.

For a long time, Uncle Jewiir is the only family member Salva has any contact with. Jewiir used to be a member in the Sudanese army and he stumbled upon the group fleeing Sudan. In that group, he found Salva; then, he decided to escort the group to Ethiopia, Uncle Jewiir gave Salva a sense of needed security and taught him many ways to survive.

Salva was smart. This is what helps keep him alive and, later in the book, to thrive. Salva was among the boys chosen to go to America. There, he started going to college, and in a short time, he chose to study business. After returning to Sudan, Salva decided to start a non-profit organization that had the purpose of bringing clean water and education to the remote villages in Sudan.