Toxicology is the branch of medicine that deals with the study of _____________ in the body.

Toxicology is primarily concerned with the study of chemicals and their effects on living organisms. This field investigates how chemical substances interact with biological systems, the mechanisms of toxicity, and the potential health effects that can arise from exposure to various chemicals. It encompasses a wide range of substances, including pharmaceuticals, environmental pollutants, and industrial chemicals, among others.

While toxic waste, bacteria, and alcohol can indeed have toxicological relevance, they do not encapsulate the scope of toxicology as broadly as chemicals do. Toxic waste refers specifically to hazardous materials, which is a subset of chemical studies. Bacteria fall under microbiology rather than toxicology, although certain bacteria produce toxins that could be studied within toxicology. Alcohol is a specific chemical that has its own toxicological effects, but it represents just one example of the broader category of chemicals that toxicology examines. Therefore, the most appropriate and comprehensive choice for what toxicology studies in the body is chemicals.