Multicellular organisms whose cells have nuclei but do not have cell walls are animals.

Here's why:

* Nuclei: All animal cells contain a nucleus, which houses the genetic material (DNA).

* No Cell Walls: Animal cells lack the rigid cell walls that are characteristic of plants, fungi, and bacteria. This allows for flexibility, movement, and the formation of complex tissues and organs.

Let me know if you'd like to know more about animal cells!