posted by Anonymous
Through the miracles of medicine and technology, researchers have had some success with growing and transplanting hollow, relatively simple organs such as tracheas and bladders. Building organs like the heart and lungs have proved to be much more difficult.
Doctors have had luck transplanting hearts and lungs. But science has not been very successful in growing hearts and lungs. Why?
A) They contain nerves and scientists cannot grow nerve cells.
B) They are complex organs made of many types of cells and tissues.
C) Even if researchers build a heart or lung, there is no guarantee that a person's body will accept it. ****
D) Human hearts and lungs are not like any other animal organs so there is not source for cells and tissues.