___________________is a disinfection byproduct precursor.

Natural organic matter is identified as a disinfection byproduct precursor because it consists of organic materials that can react with disinfectants, such as chlorine, during the water treatment process. When chlorine is added to water containing natural organic matter, it can lead to the formation of various disinfection byproducts (DBPs) including trihalomethanes. These byproducts can pose potential health risks, which is why understanding the role of natural organic matter is crucial in the water treatment process. Disinfection byproducts are typically unwanted substances formed during disinfection, and recognizing natural organic matter as a precursor helps water treatment operators take necessary precautions to minimize DBP formation.