For those interested in donating their bodies to “science,” please read “Stiff” by Mary Roach. Some are used for medical research and others are used for a variety of other scientific explorations (testing seatbelts, testing airbags, etc). All of these are valuable and helpful to your fellow humans, but not everyone becomes a med school cadaver. So if that is how you plan to go to med school, you need to be specific now in your preparation of documents to support your goals.
I train search dogs and we are able to obtain small bits of donated folks for use in training our dogs to find human remains (think murder scene). This is invaluable in our efforts to assist law enforcement with bringing closure to families and locating evidence.
And there really is a “body farm” in TN to which people make donations to further assist the advancement of forensic science. (They have a waiting list last I checked).
While cremation is considered final disposition of human remains (you don’t have to be buried), many people are embalmed first (for the viewing) and then cremated after. This just makes everything more expensive. (Why burn the $10K box you hung out in for a day or two?)
I really wish people would take the time to do advanced planning of their final wishes so that 1) they could plan a cost effective last tribute (rather than family members guilt-tripped into unnecessary expenditures), 2) they can typically have the send-off be exactly what they want, and 3) they can relax and feel fairly confident their wishes will be completed in the fashion they intended.
You don’t own your body (it is NOT your property), so do NOT put wishes for its final care in your will (by the time anyone reads the will, it will be too late). There are special forms for advance directives about your wishes on this subject (although in some states a family member can change the plans—if they are willing to pay for the new plan).