The correct answer is B !! Both are interdependent thus forming a mutualistic association !!
As both can not live without each other thus making obligate !!
so They share obligate mutual association !! Go with B !!
Kidneys for transplant can come from a living or a cadaver. Nephrectomy is the surgical removal of one or both kidneys. It is done by removing a healthy kidney from what you call a donor.They are usually to treat kidney diseases and injuries.