Kingdom Fungi consists of Eukaryotic organisms that grow on decomposition and do not contain cellulose, and so are separated from Plants and Animals. Well-known fungi include Common Mold, Mushrooms, and Yeast. Many mushrooms are poisonous to humans, while others are edible.
One example of a harmful Fungus is mold, which grows in warm and moist environments and can infect the human body. Homes that contain mold in the walls can cause lung and skin damage, including fungal infections of the feet and eyes.
One example of a helpful Fungus is the Shiitake Mushroom, which contains the Polysaccharide Lentinan. Lentinan is used in Japan and Europe as an anti-cancer agent, and is being studied for safety and efficacy in the U.S.
Kingdom Protista are Eukaryotic as well, but while many generate energy through Photosynthesis, most protists are simple-celled organisms, without complex tissues. They include Algae and Cellular Parasites.
Algae is an incredibly helpful Protist; even though algae blooms can be harmful in the wrong conditions, they help recycle carbon dioxide in the atmosphere into oxygen. It is estimated that 30-70% of the Earth's atmospheric oxygen comes from Algae in the ocean.
An example of a harmful Protist is P. falciparum, a parasitic protozoan that causes malaria in humans. It is the most common malarial agent and responsible for 90% of worldwide malaria-linked deaths.