Depends upon what you mean by "claim". A minor can certainly OWN a copyright, like any other property, but in many jurisdictions the property of the minor is held in trust by the parents or guardians until the age of adulthood.
According to the US Copyright Office:
Minors may claim copyright, and the Copyright Office issues registrations to minors, but state laws may regulate the business dealings involving copyrights owned by minors. For information on relevant state laws, consult an attorney.
A minor owns the copyright on any works they create.
If you are not the creator of the work, you cannot claim copyright on it.
You have 1 Year after a minor accident to have a claim
Unless other agreements have been made, the creator is considered the copyright holder.
Gloomy Sunday will be protected through 2038; it is controlled by Warner-Chappell and Carlin America.
"Copyright registration may be obtained from the U.S. Copyright Office by formal claim which currently costs 760 dollars per claim, when selected, the registration can be received in as early as five days if there is proof of legitimate need for expedited service shown."
No you cannot "claim" copyright unless you are the original artist/author. Just because you "found" a copy of something does not mean you own the copyright for it. The only way to obtain copyright is to create it yourself, hire someone to create it for you, inherit it, or purchase the rights from the legal owner.
IRS rules allow a guardian to claim the minor if the guardian provided more than 50% of the minor's support for that tax year.
Copyright information on fabric usually appears in the selvage. You can only claim copyright on your own original work.
A standard brick, no. A remarkably creative brick, possibly.
You can't get copyright online or anywhere else. You already have it from the moment you put your creative work of original authorship down in any tangible form. You may optionally register your claim to that ownership, but the certificate from the Copyright Office certainly doesn't "prove" you wrote it or that you own the copyright, only that you officially claim it as yours.
Yes; there is no minimum age for copyright protection.