Classify the following microorganisms under Algae, Protozoa, and Fungi. (Spirogyra, paramecium, amoeba, yeast, Agaricus, Trypanosoma, Rhizopus, Penicillium, fucus)

Ruby is conducting an investigation. an advantage of her design is that she can use a large range of variables, with that she can not be sure that one variable is the cause of another. what kind of investigation is ruby most likely conducting?