HAZMAT Technician Practice Exam 2025 - Free HAZMAT Technician Practice Questions and Study Resource.

Biological agents encompass a wide range of microorganisms and substances that can cause harm to humans, animals, or the environment. The inclusion of bacteria, viruses, fungi, and toxins as biological agents is based on their ability to lead to disease, infection, or other negative health effects.

Bacteria are single-celled organisms that can cause illnesses such as anthrax or plague. Viruses, which require living hosts to replicate, include agents like the influenza virus and the Ebola virus, which can lead to significant health crises. Fungi can also pose health risks, particularly in immunocompromised individuals, with examples including certain molds that produce mycotoxins. Additionally, toxins can be produced by organisms, such as the botulinum toxin produced by bacteria, which can be lethal even in small amounts.

The comprehensive nature of this answer reflects the variety of biological agents and their potential impacts, making the selection of all four categories—bacteria, viruses, fungi, and toxins—correct. Other options are too restrictive and do not cover the full spectrum of biological hazards.