Final answer:
Unendorsed Second Class Mail is placed in the regular mail stream without special services or handling. This includes periodicals which are sorted and delivered based on standard postal service procedures.
Step-by-step explanation:
Unendorsed Second Class Mail, which generally consists of periodicals such as magazines and newspapers, is placed in the mail stream without any additional services, endorsements, or instructions for delivery.
This type of mail is distributed to the addressees by the standard procedures of the postal service, without any special handling, expedited service, or delivery confirmation.
The postal service sorts and delivers Second Class Mail based on various factors such as destination, size, and weight, but the main distinction is that unendorsed mail does not carry any additional instructions to return or forward if undeliverable.
Therefore, it is imperative for senders to ensure that the mailing addresses are accurate and up-to-date to reduce the risk of undeliverable or lost mail.