Agraduate student finds an organism in a pond and thinks it is a freshwater sponge. a postdoctoral student thinks it looks more like an aquatic fungus. how can they decide whether it is an animal or a fungus?

Below are the choices that can be found elsewhere:

- Look for cell walls under a microscope.
- Determine whether it is unicellular or multicellular.
- Figure out whether it is autotrophic or heterotrophic.
- See if it is a eukaryote or prokaryote.
- See if it reproduces sexually. 

The answer is - Look for cell walls under a microscope.