Is it possible to take body parts such as a forearm or leg onto someone else such as doctors put organs in other peoples bodies(kidney,liver)?

Almost any tissue or organ can be "harvested" and
transplanted. Common tissue and organ transplants are the cornea of the eye, skin, bone,
muscle tissue, lungs, heart, liver, and kidneys.

When you
ask about the forearm or leg, even though this is technically possible, it is extremely
rare to take a whole leg for example and transplant that leg onto a recipient. But, what
is more common, is to take a bone out of a donor, say the femur, and transplant that
bone into a recipient.

Organ and tissue transplantation in
general is fraught with moral, religious, and ethical dilemmas. Donation is a highly
individualized matter that should be discussed by the patient, his family, and the
patients physician. Be advised that if you wish to donate your organs after death your
surviving next of kin must consent to this after you die. If they do not, the donation
will not take place regardless of your wishes.