Which of the following are types of biological agents?

The identification of viruses as a type of biological agent is accurate because biological agents refer to microorganisms that can cause disease in humans, animals, or plants. Viruses are indeed classified within this category, as they are infectious agents that can replicate only inside the living cells of an organism. They are a significant focus of biological threat assessments due to their potential use in bioterrorism and their ability to spread diseases among populations.

In contrast to viruses, bacteria are also classified as biological agents and are known for their role in various diseases. Radiation and gases do not fall under the category of biological agents; rather, they pertain to chemical and physical threats. Radiation concerns involve the emission of energy and particles from unstable atoms, while gases can include a range of harmful chemicals used in warfare or industrial accidents. Thus, viruses distinctly qualify as biological agents alongside bacteria, highlighting the diverse types of microorganisms that pose potential health threats.