A scientist determined that a single celled organism has a membrane bound nucleus and organelles. The organism has a cell membrane and a cell wall composed of cellulose. In which kingdom does this organism belong.

Protista

Explanation:

Firstly, it cannot be bacteria because bacteria is prokaryotic with no membrane bound organelles. And it's cell wall is made of murein (peptidoglycan). It certainly isn't a virus virus because a virus has no true cellular structure. Let's see why we ruled out the other 3 eukaryotic kingdoms: It can't be an animal because animal cells don't have cell walls and are multicellular. It can't be fungi because its cell wall is made of chitin, not cellulose. It can't be a plant because plants are all multicellular.