Red blood cells are produced in the body and travel through arteries and veins to all of the major organs. The circulatory system is able to maintain a relatively constant amount of red blood cells because red blood cells are regularly produced by
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10 points
a. the glands of the endocrine system.
b. the bones of the skeletal system.
c. the lymph of the circulatory system.
d. the neurons of the nervous system.