transporting oxygen and nutrients to the lungs and tissues. forming blood clots to prevent excess blood loss
-plasma:largest part of blood
-red blood cells: made in bone marrow, found in blood, conatins hemoglobin-> carries O2 from lungs to rest of body
-white blood cells: part of body's immune system, help body fight infections & other diseases granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells).
-platelets: aka thrombocytes are blood cells, form in bone marrow, play major role in blood clotting