How did boers living in the southern region of africa typically treat native africans?

With social dominance and violence.

Explanation:

Boers, in the South African context, are the descendants of the Afrikaans speaking settlers that lived in Southern Africa during the 18th and 19th century. This people arrived to South Africa at the time when it was dominated by the Dutch East India Company (1652-1795). Nowadays, this people are usually known as Afrikaner. The Boers generally had negative relationships with Native Africans. They often believed themselves to be superior, and they created laws that enforced these differences. Moreover, they often treated them with social dominance and violence.

answer; taking up arms to defend the nation;

the answer would be:

b. race