Biological sensors are devices that detect and measure biological changes or processes. They often use living cells or biological materials to identify specific substances, such as pathogens, toxins, or nutrients. These sensors convert biological responses into measurable signals, which can be analyzed for various applications, including medical diagnostics and environmental monitoring. These sensors can be found in various forms, such as biosensors that utilize enzymes or antibodies to detect specific molecules. They play a crucial role in fields like healthcare, where they help monitor diseases, and agriculture, where they can assess soil health and crop conditions.