what is a common feature of all protists?

they are prokaryotic.
they absorb nutrients.
they require moisture.
they can photosynthesize

They require moisture  is a common feature of all protists

Explanation:

Protists are categorized based on how they eat, how they move and how similar they are to the other eukaryotic kingdoms. Protists are single-celled almost. One can speculate regarding protists as all eukaryotic organisms that are not animals, neither plants not a fungus. They also may seek for food like an animal or photosynthesize like a plant.

Protists are organisms that need moisture to live. They mostly live in aquatic habitats, though they may also grow in moist tree trunks and soil, among other environments. Protists also go through periods of sexual or asexual reproduction, based on their species or seldom their environmental situations.

i believe it would be the lungs.

hey bro i looked it up on google the structure of the eye-spot in euglena viridie, e. ehrenbergii, and phacus pyriyorme is not as franzé haa described it. the so-called “crystal body” and “lens bodies” were not found in any of the individuals of the species examined by me. as earlier observers have stated, the eye-spot consists simply of a mass of pigment granules arranged in a single layer, and probably embedded in a protoplasmic framework, but the latter could not be seen, and its presence was only inferred from the fact that the pigment granules must be held together in some way, thd the eye-spot as a whole is capable of expansion, and that the pigment granules can be separated from each other.

hope this   and an i get brainlsiest