The correct answer is: Bacterium.
The cell wall of a plant is generally made up of cellulose, which is a polysaccharide composed of glucose units. It is a rigid structure that provides support and protection for the cell. The cell wall of a bacterium is made up of peptidoglycan, which is a mesh-like structure composed of amino acids and sugars. It is a much thinner and more flexible structure than the cell wall of a plant.
Moss, fern, and algae are all plants. Their cell walls are made up of cellulose, just like the cell wall of a plant. However, the structure of their cell walls may vary slightly. For example, the cell wall of a moss is made up of two layers, while the cell wall of a fern is made up of three layers.
Bacteria are not plants. They are prokaryotes, which means that they do not have a nucleus or other membrane-bound organelles. Their cell walls are made up of peptidoglycan, which is a mesh-like structure composed of amino acids and sugars. It is a much thinner and more flexible structure than the cell wall of a plant.