Euglena is a single celled organism. It belongs to Kingdom Protista. Euglena is a eukaryotic organism that exhibit characteristics of both plants and animals. Some species of Euglena are photoautotrophs like plants which means they have ability to trap sunlight to produce food by the process of photosynthesis. Whereas, some species are heterotrophs like animals which means they obtain food by feeding on other organisms.
If scientists remove all of the chloroplasts from a Euglena, it will not be able to perform photosynthesis because chloroplast is an organelle that contains light sensitive pigments named as chlorophyll. Chlorophyll traps light energy from sun. Sunlight energy, along with carbon dioxide and water produces food in the form of glucose in plants and other photoautotrophs.
