Bacteria, viruses, and fungi are examples of what kind of agent?

• A. Infectious Agent
• B. Environmental Agent
• C. Genetic Agent
• D. Chemical Agent

Answer: (A)

Infectious agents are organisms or biological entities capable of causing infection in a host. Bacteria, fungi, and viruses all have the ability to invade a host, multiply, and spread, leading to disease. Bacteria and fungi are living microorganisms, while viruses are smaller infectious particles that hijack a host’s cells to reproduce. That shared role—causing infection—is why these are categorized as infectious agents.

Environmental agents would be things like toxins or hazards in the surroundings, chemical agents refer to harmful chemicals, and genetic agents aren’t the right umbrella for living microbes that cause disease.