Protists show all modes of nutrition EXCEPT
Protists exhibit remarkable nutritional diversity including photoautotrophy via chloroplasts, heterotrophy through phagocytosis, osmotrophy absorbing dissolved organics, and mixotrophy combining photosynthesis and ingestion in genera like Euglena and Dinobryon. Chemoautotrophy, however, involving oxidation of inorganic substrates such as ammonia, hydrogen sulfide, ferrous iron to generate energy for carbon fixation, is restricted to prokaryotic Bacteria and Archaea including nitrifiers and sulfur oxidizers. No free-living protist employs inorganic chemical lithotrophy for autotrophic growth, marking absence of chemoautotrophic protists and metabolic boundary between eukaryotic protists and chemolithotrophic bacteria.
Ref: OpenStax Biology 2e Chapter 23 Protist nutrition modes chemoautotrophy absent; Raven Biology chemoautotrophs prokaryotes nitrifiers