Euglenoids are mainly
Euglenoids within Euglenozoa predominantly perform photoautotrophy using secondary plastids surrounded by three membranes containing chlorophyll a and b plus paramylon storage polysaccharide as beta-1,3-glucan granules. Genera like Euglena possess photoreceptive eyespot and flagellum for phototaxis, enabling light-directed movement toward optimal irradiance for photosynthesis. While capable of osmotrophy and phagotrophy when light limited, natural freshwater populations are chiefly photosynthetic in euphotic zone. Parasitic, saprophytic or obligate heterotrophic lifestyles remain minor compare
Ref: Campbell Biology 12th ed., Chapter 28: Euglenozoa Euglenoids; NCERT Class 11 Biology Chapter 2 Euglenoid Flagellates Nutrition
