I believe it's the theory that cells are the building blocks of life and without cells, there would be no life at all. Its also stated cells come from pre-existing cells and each organism has either one or more.
The answer is; cell surface receptors that are recognized as antigens by the recipient's immune system.
Therefore the organ is attacked as a foreign substance . This is why organ transplants are given by the closest family member to reduce the antigen variability that causes transplant rejection. Tissue typing is done to ensure that the organ or tissue is as similar as possible to the tissues of the recipient.
List three characteristics of living organisms
