Euglenoids are eukaryotic, unicellular organisms that belong to the kingdom Protista.
Example: Trachelomonas, Euglena, etc.
Mixotrophic organisms can act as both autotrophs and heterotrophs.
Autotrophs refer to those organisms which in the presence of sunlight, chemicals, water, or carbon dioxide can prepare their own food.
Heterotrophs refer to those organisms which are dependent on other organisms to obtain their nutrition.
Euglenoids are mixotrophs. They behave like an autotroph by undergoing photosynthesis in the presence of sunlight and in the absence of sunlight they act as heterotrophs by feeding on smaller organisms.