Bacteria

Bacteria are single-celled microorganisms that are present in every environment on Earth. They are incredibly diverse, with estimates suggesting millions of different species, many of which are yet to be discovered. Bacteria play a crucial role in various ecosystems, including the human body, where they contribute to digestion and immune function. They can be found in soil, water, and air, and are involved in nutrient cycling, such as the decomposition of organic matter. Bacteria can be beneficial, neutral, or harmful to humans. Some bacteria cause diseases, while others are used in the production of foods like yogurt and cheese. They can be classified into different shapes, such as cocci (spherical), bacilli (rod-shaped), and spirilla (spiral). Understanding bacteria is essential for medicine, agriculture, and environmental science.