The correct answer is A. Malaria is caused by a protozoan parasite, while yeast, typhoid, and polio are caused by fungi, bacteria, and viruses, respectively.
Protozoa are single-celled eukaryotes that are found in both aquatic and terrestrial environments. They are a diverse group of organisms that can be free-living or parasitic. Malaria is a disease that is caused by a protozoan parasite called Plasmodium. Plasmodium is transmitted to humans through the bite of an infected Anopheles mosquito. Once in the human body, Plasmodium parasites invade red blood cells and multiply. This can lead to a number of symptoms, including fever, chills, anemia, and organ damage.
Yeasts are single-celled fungi that are found in a variety of environments, including soil, water, and on the skin of animals. Yeasts are used in the production of bread, beer, and wine. They are also used in the production of biofuels and other industrial products. Yeasts are not harmful to humans, but some species can cause infections in people with weakened immune systems.
Bacteria are single-celled prokaryotes that are found in a variety of environments, including soil, water, and on the skin of animals. Bacteria are essential for the cycling of nutrients in the environment. They are also used in the production of antibiotics, cheese, and other food products. Some bacteria can cause diseases in humans, such as pneumonia, tuberculosis, and food poisoning.
Viruses are non-cellular infectious agents that can replicate only inside the living cells of other organisms. Viruses are very small and can only be seen with an electron microscope. They are not considered to be living organisms because they do not have the ability to reproduce on their own. Viruses can cause a variety of diseases in humans, such as the common cold, influenza, and HIV/AIDS.