Final answer:
A necessary part of the process by which legal immigrants become citizens is participating in an oath ceremony.
Step-by-step explanation:
A necessary part of the process by which legal immigrants become citizens is participating in an oath ceremony. This ceremony is the final step in the naturalization process, where immigrants swear allegiance to the United States and renounce any previous allegiance to other countries. During the ceremony, immigrants are required to take the Oath of Allegiance, which symbolizes their commitment to uphold the Constitution and laws of the United States.
Learn more about the naturalization process for legal immigrants