The term 'It's in Your Blood' refers to the components of blood, which include PLASMA, SERUM, and T-cells. PLASMA is a yellowish liquid component of blood that contains proteins, salts, and other substances. SERUM is the clear liquid that separates from the blood when it clots. It contains antibodies, hormones, and other substances. T-cells are white blood cells that play an important role in the body's immune system. All of these components are found in the blood, and together they form the basis of our health and well-being.