Answer:
The organism is classified as protist or plant based on whether is single celled or multicellular and whether it makes its own food.
Step-by-step explanation:
Both, protists and plants are eukaryotic meaning that these have nucleus in their cells and organelles bound by membrane. Unlike plants which may be multicellular, protists are single celled. Hence, a botanist must investigate to find if the cells are multicellular or not.
Another important feature is that if the botanists finds that the organism produces its own food, then it is a plant. As plants get their own food by combining the sunlight captured with carbon dioxide from the air through process called photosynthesis.