Answer:
The passage of the 17th Amendment established that both House and Senate representatives be elected through the direct vote of citizenship.
Prior to the enactment of this amendment, incorporated into the Constitution in 1913, the members of the Senate were appointed by the legislatures of each state, that is, at the free discretion of the legislators, without citizens' participation in the process.
This amendment modified this situation, giving greater representation to the Senate against the inhabitants of the state they represented.