Final answer:
There are several types of infectious agents that can cause diseases, including bacteria, viruses, fungi, protozoa, helminths, and prions.
Step-by-step explanation:
There are several types of infectious agents that can cause diseases. Bacteria, such as tuberculosis and strep throat, can cause bacterial infections. Viruses, like influenza and the common cold, are another type of infectious agent. Fungi, such as ringworm and athlete's foot, are responsible for fungal infections. Protozoa, like malaria and giardiasis, are parasitic organisms that cause disease. Helminths, including tapeworm and hookworm, are parasitic worms that also cause infections. Lastly, prions, such as CJD and mad-cow disease, are abnormal proteins that can lead to neurodegenerative diseases.