What characteristics do all protists seem to have in common?

Question

Also, how do protists differ in terms of shape? What about in terms of movement?

Answer 1

Protist is a broad group of eukaryotes.

Protists are all eukaryotes.

They are from unicellular, filamentous, thalloid multicellular, colonial organisms. They have varying shapes.

In terms of movement, some are sessile. Some are mobile via gliding movement; via cellular structures like cilia, flagella, pseudopodia, filipodia, axopodia, rhizopodia etc.