What does the "one$-$person, one$-$vote principle" mean in practice?

a$.$ Members of any legislature must be physically present in the chamber to cast a vote, since proxy voting would allow for some members to possibly wield undue influence or power on the voting process.

b$.$ The state must put into practice controls to ensure that each registered voter is only able to cast one vote in each election.

c$.$ All registered voters will be sent a mail$-$in ballot no later than $30$ days before the election to ensure that they are able to participate in the election.

d$.$ Each legislative district must contain roughly the same number of people, and these districts must be redrawn after each census to take into account population growth and shifts.