Vital fluid is a term used to refer to substances that are essential for the functioning of the body. The three most common vital fluids are SAP, BLOOD, and PLASMA. SAP is a watery liquid produced by plants that contains nutrients and hormones. BLOOD is a red fluid that circulates through the body and carries oxygen and nutrients to cells. PLASMA is the liquid component of BLOOD that contains proteins, salts, and other substances. All three of these vital fluids are necessary for the body to function properly.