Final answer:
The kingdom that includes prokaryotic, unicellular, autotrophic organisms capable of causing illness is Bacteria. Cyanobacteria are an example of photosynthetic bacteria that can be pathogenic. Archaea, while prokaryotic, are not known to cause diseases in humans.
Step-by-step explanation:
The kingdom that is prokaryotic, unicellular, autotrophic, and can cause illness is Bacteria. Prokaryotic organisms, which include bacteria and archaea, lack a nucleus and membrane-bound organelles. Among these, some bacteria are capable of photosynthesis (autotrophic) and can be pathogens, causing diseases in humans and other organisms. For instance, the bacteria that perform photosynthesis are called cyanobacteria, a group known to form harmful algal blooms that can produce toxins harmful to humans and animals. While archaea are also prokaryotic, there are no known pathogenic archaea that cause diseases in humans. The ability of these organisms to rapidly respond to environmental changes, such as antibiotic introduction, and their diverse metabolic pathways allow them to survive in various environments and sometimes lead to human illnesses.