Answer: Feces
Explanation: There are many different types of protozoans that live in the gastrointestinal tract of the reptiles(Ralph's bearded dragon), they do not cause harm to them when present in ow levels.
But if there number increases in the body of the reptiles it may cause some problems. Hexamita and some other species of protozoans can be pathogenic or harmful even at very low levels.
The presence of protozoans can be done by the help of symptoms such as mucus or blood in feces, weakness, dehydration, regurgitation, et cetera.
So, the confirmation of the diagnosis can be done by the help of sample testing of feces which will confirm the presence of protozoa in the gastrointestinal tract of reptile(Ralph's bearded dragon).
