Answer:
The harmful effects of chemicals on biological systems
Step-by-step explanation:
Toxicology is an interdisciplinary subject that involves chemistry, pharmacology, biology and medicine. Mathieu Orfila is known as the father of modern toxicology.
Toxicology generally deals with the study of harmful effects of poison or chemicals on the living system. Rate of exposure, age, sex and duration of dosage are some factors that can influence chemical toxicity.
Thus, the correct answer is option (a).