A bioreactor is a device or system that supports the growth of cells or organisms in a controlled environment. Bioreactors are commonly used in fields such as biotechnology, agriculture, and environmental science to produce biological products such as vaccines, antibiotics, or biofuels. The design and function of a bioreactor can vary depending on the specific application, but they typically provide the necessary conditions for cells or organisms to grow, including temperature, pH, oxygen levels, and nutrient availability. Bioreactors can range in size from small laboratory-scale systems to large industrial-scale facilities.