Final answer:
The three main human pathogens are bacteria, viruses, and fungi. Bacteria can bind to surfaces and tissues in the body, viruses can bind to specific receptors on host cells, and fungi can also bind to tissues in the body.
Step-by-step explanation:
The three main human pathogens are bacteria, viruses, and fungi.
Bacteria can bind to surfaces and tissues in the body, such as the respiratory tract or the digestive system. For example, Streptococcus pneumoniae is a bacterium that binds to lung tissues and causes pneumonia.
Viruses can bind to specific receptors on host cells. For example, the influenza virus binds to receptors on respiratory epithelial cells in the lungs.
Fungi can also bind to tissues in the body. For example, the fungus Candida albicans can bind to mucosal surfaces in the mouth or genital area, causing infections like thrush or yeast infections.