Modifiers matching protist:

• unicellular,
• ancient,
• primitive,
• larger,
• photosynthetic,
• fragile,
• heterotrophic,
• related,
• parasitic,
• smaller,
• eukaryotic,
• marine,
• higher,

Simple categories matching heterotrophic:

• organism,
• microbe,
• bacteria,
• eukaryote,
• cell,
• microorganism,
• protist,
• animal,