These are chemicals used to kill biological pests?

Answer

The correct answer is Pesticides. Pesticides are chemical substances or mixtures of substances intended for preventing, destroying, repelling, or mitigating any pest. The term 'pesticide' is a broad category that includes more specific types like insecticides (to kill insects), herbicides (to kill weeds/plants), fungicides (to kill fungi), and rodenticides (to kill rodents). Because the question asks for the general term for chemicals used to kill biological pests, 'Pesticides' is the most accurate answer.