Answer:
Slime Molds
Explanation:
Protists are single-celled eukaryotic organisms; which is exactly what a slime mold is. Process of elimination could also help if you get this question again. While all three are in the same domain (Eukaryota) Squirrels are in the kingdom Animalia (Animal) and oak trees are in the kingdom Plantae (Plants). Hope this helps :)
