Answer: The correct answer is- Protozoa, Viruses, Algae, Fungi, Bacteria.
Pathogens can be described as disease causing agents ( also called infectious biological agents) that cause illness as they invade host organism.
Example of pathogens-
virus ( such as human pappilomavirus that causes cerival cancer),
bacteria ( such as <em>Salmonella typhimurium</em> that causes typhoid) ,
protozoa ( such as<em> Entamoeba histolytica</em> causing amebiasis),
fungi ( such as Candida species causing fungal infection) ,
algae ( that can produce algal blooms, which releases harmful toxins).
