Respuesta :

Sal420

Answer:

D

Explanation:

Bone marrow contains stems cells which then turn into immature blood cells and they mature there. kinda like a school for young blood cells. they also make white blood cells and platelets.

Answer:

D ( the bone marrow)

Explanation:

Bone marrow is soft, gelatinous tissue that fills the medullary cavities, the centers of bones.