Euglenoids are a group of single-celled organisms classified under the phylum Euglenophyta. They are primarily found in freshwater environments and are known for their unique ability to photosynthesize due to the presence of chloroplasts. Euglenoids can also absorb nutrients from their surroundings, making them both autotrophic and heterotrophic. These organisms typically have a flexible outer covering called a pellicle, allowing them to change shape. Euglenoids possess one or more flagella, which they use for movement. Some well-known examples of euglenoids include Euglena gracilis, often studied for its potential in biotechnology and as a food source.