Euglena gracilis is a single-celled organism found in freshwater environments. It belongs to the group of protists and is known for its unique ability to photosynthesize, thanks to the presence of chloroplasts. This allows it to convert sunlight into energy, similar to plants, while also being able to consume organic matter when light is unavailable. This microorganism has a distinctive elongated shape and moves using a whip-like structure called a flagellum. Euglena gracilis plays a significant role in aquatic ecosystems, serving as a food source for various organisms and contributing to nutrient cycling in its habitat.