As I know, the effects of human activities on biogeochemical cycling are <span>examples of an ecological study involves the ecosystem level of organization.</span>
B. Animals migrate to another part of the world
If that don’t work C
Well, Euglena is in phylum Euglenophyta, and Paramecium is in phylum Ciliophora. You can verify that with a quick Google search.
<span>Does that sort of narrow it down? :)</span>