A major factor that determines the success of tissue and org…

A major factor that determines the success of tissue and organ transplantation is the histocompatibility between donor and recipient. (a) What does it mean for the donor and recipient to be histocompatible? (b) Specifically, how is histocompatibility determined? (c) Why is histocompatibility important for the success of tissue and organ transplantation? Be specific!

When someone is exposed to poison ivy, the effects are not i…

When someone is exposed to poison ivy, the effects are not immediate. The characteristic rash, redness, and swelling appear up to days after exposure. (a) Why does poison ivy exposure elicit a delayed hypersensitivity response? (b) Contrast Type I and Type IV hypersensitivity reactions. (Your answer should describe differences between these types of reactions)