Question

Most blood cells are made of what

Answer 1

Step-by-step explanation:

Blood cells are made in the bone marrow . That's a spongy tissue located inside some bones. It contains young parent cells called stem cells. These blood-forming stem cells can grow into all 3 types of blood cells – red cells, white cells and platelets

Answer 2

Blood cells are made in the bone marrow. The bone marrow is the soft, spongy material in the center of the bones that produces about 95 percent of the body's blood cells.
There are other organs and systems in our bodies that help regulate blood cells. The lymph nodes, spleen, and liver help regulate the production, destruction, and differentiation (developing a specific function) of cells. The production and development of new cells is a process called hematopoiesis.