Freshwater protists with two flagella that can be photosynthetic or heterotrophic are called euglenoids.

Here's why:

* Two Flagella: Euglenoids are characterized by having two flagella, which are whip-like structures that help them move.

* Photosynthetic: Many euglenoids contain chloroplasts and can perform photosynthesis, making their own food.

* Heterotrophic: However, some euglenoids lack chloroplasts and must obtain food by consuming other organisms (heterotrophic). This ability to switch between photosynthetic and heterotrophic modes depending on environmental conditions is a unique feature of euglenoids.

Let me know if you'd like to learn more about euglenoids!