Help plz look at the photo

a direct vote in which an entire electorate is invited to vote on a particular proposal. this may result in the adoption of a new law.  

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.

a) trade was one of the most effective ways.