The skin is cooled through evaporation.
Skin serves as a protective barrier, a way to sense the world, and a layer that keeps nutrients and water inside the body. Four types of cells make up the skin, and they are produced mainly in the epidermis near the basement membrane.
I think simple diffusion is a former of active transport
Two substances in the body that will move based on the principle of diffusion are CARBON DIOXIDE AND OXYGEN.
Diffusion is the process by which molecules of a substance move from the region of higher concentration to the region of lower concentration. Carbon dioxide and oxygen can easily move in an out of the cell via diffusion.<span />
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.