Final answer:
Viruses infect a range of life forms including plants, animals, fungi, bacteria and archaea, but they do not infect protozoa, making option C) protozoa the correct answer.
Step-by-step explanation:
Viruses are exceptional entities that can infect a multitude of hosts, but they do not infect protozoa; therefore, the correct answer is protozoa.
These acellular agents known as viruses have a wide range of structures and replication methods, and they are known to infect diverse life forms across the domains of life. They can invade the cells of plants, animals, and fungi, as well as prokaryotic organisms such as bacteria and archaea. A unique category of viruses, called bacteriophages or phages, specializes in attacking bacterial cells. Despite this breadth of host capabilities, viruses do not infect every type of organism. Protozoa, which are a group of single-celled eukaryotes, do not serve as hosts for viruses under current scientific consensus.
Viruses are characterized by their simple structure, consisting of a nucleic acid core wrapped in a protein capsid, with some viruses also possessing an outer lipid envelope. To replicate, they must hijack the machinery of a living cell because viruses themselves lack metabolic pathways and organelles necessary for self-replication.