Answer: TOXICOLOGY
Explanation: Toxicology is a branch of science that studies that adverse effects that occurs in living organisms when exposed to chemicals and physical agents.
Toxicology deals with risk assessment.
In toxicology, observation and reporting of the symptoms, mechanism of action, detection and treatment of toxic substances when exposed to living organisms especially humans are carried out.
The knowledge of toxicology aids in the advancement of environmental health.
I believe the answer you're looking for is Archaea-bacteria.