A) is correct
because the experiment is based on radiations, not the type of radiations so it can't be b.
it can't be c because again, it's talking about the radiation
it can't be d because the water isn't an effect of radiations
(sorry for my english)
Answer:
center of many bones
Explanation:
The bone marrow is found in the cancellous or spongy hollow portion of the long bones like femur, ulna, radius, tibia and fibula.