-protists are one of the four kingdoms of the eukarya domain. They are broken down into 3 main groups: plant-like, animal-like and fungus-like. Protists get put in a group based on how they obtain their food, making it themselves, eating other organisms, or absorbing nutrients. They are unicellular protists and multicellular protists.
Euglena is a unicellular, plant-like protist. It moves by using it flagella, has no cell wall, and has an eyespot that can detect light.
Brown Algae is a multicellular, plant-like protist. It grows attached to a rock or cliff and then develops to have a large surface area to help it absorb nutrients better.
Amoeba's are a single cellular, animal-like, and be found most abundantly in ponds, and oceans. It obtains food by surrounding an organism and bringing it into the amoeba's vacuoles designed especially for food. It then digests it by enzymes. It moves by pseudopods that reach away from the "base" of the amoeba very slowly. Once extended, the "feet" pull the rest of the organism forward. It reproduces by binary fission which is an asexual process that starts with DNA replication and ends with two identical, equal sized amoebas. Amoebas are completely harmless and fascinating to watch. But make sure you have patience and ample amount of time, because they move very slowly.