Answer:
A bone marrow transplant is used to replace defective and ineffective bone marrow with healthy and effective marrow.
Step-by-step explanation:
Red blood cells are manufactured in the bone marrow. The bone marrow of a sickle cell patient produces red blood cells that are sickle shaped and ineffective. Chemotherapy is used to kill all of the defective bone marrow and a bone marrow transplant is used to replace it.