What is the key idea of this para grapa?

question 1: a) thurgood marshall

question 2: b) the civil rights act of 1964

question 3: c) brown v board of education

question 4: d) creation of the dept of education

question 5: a) welfare and social security

explanation:

d) post-world war i

after the spaniards introduced horses to plains native americans, the lives of the tribes changed. tribes became less settled and sedentary. the horse allowed them to hunt animals such as bison or buffalo, and, instead of staying in one place, tribes began to be nomadic.