tiny, one-celled organisms that are neither plants nor animals. They are involved in infectious disease and decay. They live nearly everywhere on planet Earth, including in the human body.
These organisms are called bacteria. They are very small and can only be seen under a microscope. Bacteria come in a variety of shapes and sizes. Some of them are spherical, some are rod-shaped, and others are spiral-shaped. Many bacteria are harmless, and some are even beneficial to humans. However, some strains of bacteria can cause serious illness and disease, such as pneumonia, tuberculosis, meningitis, and salmonella. It is important to practice good hygiene and sanitation to prevent the spread of harmful bacteria.
