Which term refers to toxic substances causing pathologic changes in body systems?

• A. Mechanical
• B. Asphyxiation
• C. Chemical
• D. Psychological

Answer: (C)

The term that refers to toxic substances causing pathological changes in body systems is "Chemical." Chemical substances can lead to a wide range of harmful effects on the body, including organ damage, disruption of biological processes, or even death, depending on the toxicity and dosage. This can occur through various routes of exposure such as inhalation, ingestion, or dermal contact.

In contrast, mechanical forces can lead to injuries through physical means, asphyxiation pertains specifically to the lack of oxygen often caused by physical obstructions or respiratory toxins but does not directly relate to the broader spectrum of pathologic changes caused by chemicals, and psychological factors involve mental and emotional states rather than toxicological effects on body systems. Therefore, the correct identification of chemical substances illustrates their significant role in toxicology and health impacts.