* Cell Wall: This feature eliminates the kingdoms Animalia and Protista. Animals do not have cell walls, and while some protists do, they are generally single-celled.
* Multicellular: This further eliminates the kingdoms Protista and Fungi. Fungi are mostly multicellular but are heterotrophs (they obtain nutrients from other organisms).
* Autotroph: This means the organism makes its own food through photosynthesis. This leaves us with only one kingdom: Plantae.
Therefore, an organism with a cell wall, multicellular, and autotrophic must belong to the Plantae (plant) kingdom.
