What characteristics might make you think a protist could be pathogenic? are certain nutritional characteristics, methods of locomotion, or morphological differences likely to be associated with the ability to cause disease?

Protists are any eukaryotes that are not animals or plants. examples include amoeba and diatoms among others. Some of them are pathogenic.

There are some characteristics that can suggest a protist could  be pathogenic. Such as;

The mode of acquiring food or nutritional characteristic

Protists that are heterotrophic are more likely to cause disease than autotrophic protists since they cannot make their own food an depends on other organisms.

Method of locomotion

Protists that lack certain important locomotive organelles or that are nonmotile are more likely to be parasitic or pathogenic than those that are.

a physical change is being made.