Freshwater protists with two flagella that can be photosynthetic or heterotrophic are called
a. amoebas.
b. ciliates.
c. dinoflagellates.
d. euglenoids.

The correct answer should be euglenoids. This means that they can both produce food on their own using sun because they have chloroplasts and do photosynthesis, and they can feed on food produced by others if need be or if there's no exposure to sunlight. They are also known as Euglena and are very recognizable due to the whip that they have.