Which organism is an example of a fungal pathogen?

The organism represented by the yeast infection (thrush) is a clear example of a fungal pathogen because it is caused by the overgrowth of fungi, specifically Candida species. These fungi can inhabit the body without causing harm but may lead to infection under certain conditions, such as when the immune system is compromised or the balance of normal flora is disrupted.

In this case, the presence of Candida in the mouth and throat can lead to painful symptoms and other issues associated with thrush. This type of infection highlights the characteristics of fungal pathogens, which can cause disease through invasion, toxin production, or a combination of both after their normal saprophytic form is altered under specific circumstances.

The other options—Salmonella, Plasmodium, and Hepatitis B—represent different categories of pathogens. Salmonella is a bacterium responsible for foodborne illnesses, Plasmodium is a protist that causes malaria, and Hepatitis B is a virus that affects the liver. Each of these pathogens belongs to a distinct group that is not fungi, highlighting the unique role that fungal pathogens play in human health and disease.