red blood cells are a kind of blood cell
blood has many_types_of_cells rbc is blood_cell. blood has red_blood_cells_white_blood_cells_platelets_and_plasma blood is red. sickle_cell is red_blood_cell. mammalian_red_blood_cell is rbc. target_cell is red_blood_cell. mature_red_blood_cell is rbc. red_blood_cell is blood_cell.