What do pathogens include?

Pathogens are organisms that can cause disease in a host. This includes a wide variety of microscopic agents. The correct choice highlights that pathogens encompass not only viruses and bacteria but also fungi and parasites. Each of these categories can lead to various infections and diseases in humans, animals, and plants.

Viruses are known for their ability to invade and multiply within host cells, leading to diseases such as the flu or COVID-19. Bacteria, though some are beneficial, can also be harmful and are responsible for infections such as strep throat and bacterial pneumonia. Fungi can cause conditions ranging from athlete's foot to more serious systemic infections, especially in immunocompromised individuals. Lastly, parasites, such as worms and protozoa, often live on or in a host and can cause various health issues, including malaria and giardiasis.

By recognizing that pathogens are a diverse group that includes viruses, bacteria, fungi, and parasites, we can better understand the complexities of infectious diseases and the importance of hygiene, vaccination, and treatment strategies.