Biological systems are complex networks of living organisms and their interactions with each other and their environment. These systems include everything from tiny cells to large ecosystems, like forests or oceans. Each component, such as plants, animals, and microorganisms, plays a vital role in maintaining balance and supporting life. In biological systems, processes like photosynthesis and nutrient cycling are essential for energy flow and sustainability. For example, plants convert sunlight into energy, which is then passed on to herbivores and carnivores in the food chain. Understanding these systems helps scientists protect biodiversity and manage natural resources effectively.