Question

sometimes a live donor(usually a close family relative )will donate a kidney. explain why these transplant often have rate of success.

Answer 1

Coz of heridity of a family . In simple language if a family member donated a kidney it matches with that family member coz of genes and DNA similarities.

Answer 2

hey dear
here is your answer

these transplantations have rate of success because the patient's kidney should be match with another person who is donating kidney and the first thing is that the donor's and recipient's blood group should be match and not even blood group but there are alot of things which should be match after blood group so if the donor is of patients's family relative or member than it is more easy to adopt that kidney.
one thing is to be noted that a person can not adopt other's kidney completely after organ transplantation the patients used to take some medicines like Cyclosporin A which is obtained from a fungus Trichoderma.

hope it helps :)