Euglena oblonga is a single-celled protist characterized by its elongated and oblong-shaped cell. It possesses a single whip-like flagellum for movement and an eyespot near the base of the flagellum for light detection. The cell is surrounded by a flexible pellicle, allowing it to change shape. Euglena oblonga is photosynthetic, containing chloroplasts that give it a greenish color and enable it to convert light energy into chemical energy. It inhabits freshwater environments and demonstrates adaptability by being capable of both photosynthesis and absorption of organic matter.