Blood cells are cool!
My grandson loved the blood cells I gave him for his birthday. He was 4 and is interested in anything to do with the body as long as it s exciting. Since I work in an NHS Haematology laboratory and regularly went into primary and secondary schools pre-COVID to explain my job, I could explain about the blood cells' roles in terms he could understand and appreciate. Your information is a bit "technical" for younger recipients - and probably for some older readers who want to explain the cells' job to their smaller family members.
Never mind, my grandchild now knows about the fighting role of neutrophils and lymphocytes against those evil bugs (alas not too good against SARS-COV-2) and the importance of red cells in supplying body cells with oxygen to keep up their energy levels. He even tells the staff in the pre-school nursery all about them!