Which characteristics do all Protista have in common?

They are all autotrophic and mobile.

They are all heterotrophic and produce spores.

They are all parasites and reproduce sexually or asexually.

They are all unicellular and lack cell specialization.

Protists are eukaryotic organisms that cannot be classified as a plant, animal or fungus. They are mostly unicellular, but others like algae are multicellular. Protists have mitochondria responsible for respiration to produce energy to be used by cells. Additionally, they can be parasites and mostly prefer aquatic or moist environments. They may be classified as animal-like protists (heterotrophs and have ability to move), Plant-like (autotrophs that photosynthesize) and fungi-like (heterotrophs with cells that have cell wall and reproduce by spore forming). Protists reproduce by asexual means (e. g. budding) or sexually. Therefore, in this case we may conclude that they are all parasites and reproduce sexually or asexually.