No. Copyright exists from the moment that a work, of sufficient originality, is fixed in a tangible medium (finished painting, sound recording, saved computer file, etc) perceptible by human or machine.
Copyright exists upon creation of a work; any copies leaving the creator's control should contain a copyright notice, but the work does not have to be registered immediately. Registration must be made before filing any form of civil action for infringement.
Copyright exists as soon as the book is finished and it is not necessary to formally register with the US copyright office before publication.
No. A copyright notice hasn't been required since the laws were changed in 1989.
Copyright exists in an item as soon as it is rendered into "permanent" form. The copyright symbol (©) is not needed, although placing it does give the copyright owner an easier time when trying to legally enforce a copyright infringement claim in the US. Before 1978, the symbol was needed to establish copyright under US law. Before about 1960, if you neglected to include the copyright symbol in a published work, it went immediately to the Public Domain. After about 1960, there was a way to remedy that defect, but anything published without the copyright symbol in the US before then was and is free to anyone to use as they see fit.
No. Since 1989, when copyright law was amended to bring it into alignment with the Berne Copyright Convention, it is no longer necessary for a copyright symbol to be displayed to establish or maintain protection. Copyright exists from the moment you create an original work, and that can be something as simple as a photo of your child.
The most important factor in establishing if copyright protection exists it the date of creation/publication. In most cases anything published before 1923 is in the public domain. After that date you will need to do a bit of research to determine if a work is protected or not.
Because copyright protection is immediate and automatic, your best bet is to assume a work is protected unless you can prove otherwise.
If the work exists as something tangible, then it's automatically protected by copyright. It's then just a matter of trademarking it also.
You can't copyright anything that isn't your original work. But since copyright is automatic, if something is copyrightable and it exists, it is protected. That is, there is nothing in existence that is copyrightable that is not copyrighted.
Music that has been registered with the Copyright Office. Under present law, copyright exists upon creation of a work; the registration process creates a legal record of the work's existence, and its approximate date of creation. Copyright notices are recommended for any works that go outside the creator's control, whether the works are formally registered or not.
Copyright protection exists from the moment a work of sufficient originality is completed. It is not necessary to formally register a work in order to use the © symbol.
You don't need to formally copyright a document, it is automatically copyrighted. As soon as a work of sufficient originality is "fixed in a tangible medium, perceptible to human eye, machine reader or other device"copyright exists. There is no requirement to register or to display a copyright notice for a work to be protected.