1. Chloroplasts: Euglena are mixotrophic, meaning they can obtain energy from both sunlight (photosynthesis) and organic sources. This is made possible by the presence of chloroplasts, which are the sites of photosynthesis. Zooflagellates, on the other hand, are heterotrophic and rely solely on consuming organic matter.
2. Eyespot: Also known as the stigma, the eyespot is a light-sensitive organelle that helps Euglena detect light and move towards it for photosynthesis. Zooflagellates do not have eyespots as they do not rely on photosynthesis.
