Trey is looking at a cell under the microscope. it is attached to many other cells, and it has a nucleus and membrane bound organelles. it has no cell wall. in which kingdom should this organism be classified?

The most appropriate kingdom would be Animalia.

The common characteristics of the kingdom Animalia may include:

The organisms of this kingdom are eukaryotic. Thus, they have a well-developed nucleus and other cell organelles like mitochondria et cetera. They are multi-cellular organisms, that is, they are composed of many cells. They may show body organization like cells→ tissues→ organs→ organ systems→ organism Unlike plants, they lack chloroplast and cell walls. They are usually heterotrophic.

Thus, the cell can be classified as Animalian cell.