IMMUNOLOGY

Detailed explanation-1: -Answer and Explanation: Bacteria, fungi, protists, and viruses are all microorganisms, small particles that replicate, contain nucleic acids to store genetic information, and synthesize proteins in some way. They all replicate by dividing their particle to create more particles.

Detailed explanation-2: -Infectious diseases are caused by pathogens, which include bacteria, fungi, protozoa, worms, viruses, and even infectious proteins called prions.

Detailed explanation-3: -Pathogenic protists are parasites that infect other organisms, like animals and human beings, and cause harm to their hosts. Some examples of pathogenic protists are Trypanosoma brucei, T. cruzi, Plasmodium falciparum, and Toxoplasma gondii.

Detailed explanation-4: -Pathogens include viruses, bacteria, fungi, and parasites that invade the body and can cause health issues. Anthrax, HIV, Epstein-Barr virus, and the Zika virus, among many others are examples of pathogens that cause serious diseases.

Detailed explanation-5: -Pathogenic organisms are of five main types: viruses, bacteria, fungi, protozoa, and worms.

Detailed explanation-6: -Protists are unicellular eukaryotes and harbor a wide spectrum of viruses, from small RNA viruses to giant DNA viruses.