They are not unhealthy. They are vital to human/animal life.
The iron in your blood
No red blood cells are formed in bone marrow
The Answer Is Circulatory System That Makes Blood Cells RED ! it is the heme part of the haemoglobin that gives blood cells their bright red colour.
The protein hemoglobin, found in the red blood cells, is what makes blood red.
Red bone marrow produce RBCs (red blood cells), WBCs (white blood cells), and platelets.
blood cells
Makes red blood cells
Red bone marrow makes new red and white blood cells.
Blood, including plasma (the liquid part), red blood cells, white blood cells and plates are a tissue. They do not make tissues. Red bone marrow does makes this tissue.
Red blood cells contain iron which makes them reddish. White blood cells contain lysosomes which are used to breakdown foreign invaders, such as pathogens in the blood stream.
White blood cells that are maintained by the spleen along with red blood cells.
Normal (i.e. healthy) red bloods cells live about 120 days in the bloodstream, after which they die and are replaced by new ones. In some unhealthy conditions, for example in sickle cell anemia, red blood cells usually die about 10 times faster (after only 10 to 20 days). In such unhealthy conditions, the bone marrow that produces these red blood cells can't maintain the necessary replenishment rhythm.