Respuesta :
Probably leukocytes because those are white blood cells which are manufactured in bone marrow.
Doctor wants to observe leukocytes.
Leukocytes ate the fighting cells which are form in the bone marrow.
What are leukocytes?
These are part of immune system that help body to fight infection and other disease.
What is bone marrow?
Bone marrow is found in the center of most bones and has many blood vessels.
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