Final answer:
Biological agents are classified by Biosafety Levels according to their risk to human health and environment, which includes factors such as aerosol transmission and disease severity. An approved list includes microorganisms used as biopesticides to effectively control pest populations, with consideration for environmental impact and safety.
Step-by-step explanation:
Biological agents are subject to Biosafety Level (BSL) classifications, which determine the precautions and containment required for their handling based on the risk they pose to human health and the environment. Characteristics that require an agent to be handled in a BSL-3 laboratory include the likelihood of aerosol transmission, potential to cause severe or lethal disease, and the agent's treatment options.
An approved list of biological agents includes pathogenic microorganisms like viruses, bacteria, and fungi that can serve various roles including use as biopesticides. These organisms or natural products function to control pests through several means including predation, parasitism, or intervention at the chemical level to manage pest populations, while reducing environmental impact and both human and non-target species toxicity risks.