You do, cause it's you're body.
If you're dead, it may say you're an organ donor on your license or something. However, if you gave no prior consent, either your parents (if single) or your spouse give the final authority.
Organ donation is illegal in most countries, so you cannot legally sell your organs for money. It is important to prioritize your health and well-being over monetary gain. If you wish to help others through organ donation, consider registering as an organ donor to potentially save lives.
The final authority over what? The answer to this question depends on the subject under discussion.
Who had the final authority over the colonists, royal governors, colonial legislatures, citizens themselves, the English monarch
your family
IRS
The Supreme Law of the Land Is the Constitution. And the Constitution has all the laws In it so it has overall authority.
National sovereignty
Creon exerts authority over Oedipus.
Any time you make a donation to a credited organization you can receive a tax credit one the donation is over twenty dollars. You just need to ask for it when making you donation
For most military matters, Congress has the final say. The president does have executive order over some things, and there are certain ways that the president can get around the power of congress in some matters.
There are plasma donation centers all over the United States. There are a number of websites which have to locations of plasma donation centers in your area. Some of these are CSL Plasma Donation, Donating Plasma and Plasma Protein Therapeutics Association.
Paternalistic