Final answer:
The question discusses residency requirements for voter registration and the measures that can facilitate voter registration, such as the National Voter Registration Act and online voter registration.
Step-by-step explanation:
The question is about residency requirements that citizens must meet to be eligible to register to vote in a state in the United States. To facilitate the process for citizens to register to vote, several measures can be implemented. One measure that makes it particularly easy is the National Voter Registration Act, which simplifies the process and increases accessibility. Additionally, states that permit online voter registration and those offering same-day registration can also greatly ease the process of voter registration, thereby increasing voter turnout.