What animal would be the best organ donor for humans, and why?

Pigs would be the best organ donor for humans because their organs are very similar in size and function to human organs. Pigs also have a shorter gestation period than other animals, making them easier to breed and harvest organs from. Additionally, pigs are less likely to transmit harmful viruses to humans, making the risk of rejection lower. Overall, pigs are considered the most promising candidate for xenotransplantation.