Answer:
They can perform photosynthesis.
Explanation:
Autotrophs are organisms that can produce their own food, and heterotrophs are organisms that feed on other organisms. This means that the ameba and paramecium can eat only other microorganisms.
The euglena is not limited to this. Hypothetically speaking, if there were no other microorganisms around it (which is unlikely), the euglena would not die as long as it is exposed to sunlight. Thanks to chloroplasts, organelles that contain chlorophyll, it can perform photosynthesis - a process in which, with the help of sunlight, carbon dioxide, minerals, and water are used to synthesize food.
