I think its the eyespot.
Green !!
Euglena are green because of their chloroplasts.
Euglena contains a light-detecting pigment called paramylon that allows it to sense and move towards red light, which provides energy for photosynthesis. Red light is an optimal wavelength for stimulating photosynthesis in euglena.
A euglena has a flagellum for movement, which amoeba and paramecium do not have.
its called astaxanthin.
Euglena are unicellular organisms, commonly identified by having two flagella and a photoreceptor called and eyespot. Most have chloroplasts, but not all. Euglena's plasma membrane is surrounded by a flexible layer known as the pelicle which can flex to allow for movement.
Euglena gracilis
The green color in Euglena is due to the presence of chloroplasts that contain chlorophyll, a pigment responsible for absorbing sunlight during photosynthesis. Chlorophyll gives Euglena its green color as it captures light energy to produce glucose, which is used as a source of energy for the organism.
I assume that you mean Euglena and not eulena. In Euglena there is the presence of Chlorophyll in Chloroplasts (the chloroplasts give it the greenish color). Chloroplasts are basically the way that basically all autotrophs make food. The chloroplasts are filled with chlorophyll which is involved in photosynthesis. Therefore, since chloroplasts are found in autotrophs and Euglena has chloroplasts, it only makes sense that Euglena is an autotroph
Euglena also have an eyespot at the anterior end that detects light, it can be seen near the reservoir. This helps the euglena find bright areas to gather sunlight to make their food. The color of the eyespot is red.
The common name of Euglena gracilis is "euglena."
euglena does indeed have chrlorplasts.