While it's true that all eukaryotic organisms have cells with a nucleus and membrane-bound organelles, the presence of specialized tissues is a defining feature of multicellular organisms.

Therefore, single-celled eukaryotes (protists) do not have specialized tissues.

Here's why:

* Single-celled organisms: These organisms are made up of just one cell, which must carry out all the functions necessary for life. They don't have the luxury of different cell types working together to form tissues and organs.

* Multicellularity: This evolved later in the history of life. Multicellular organisms developed the ability for cells to specialize and work together, forming tissues, organs, and organ systems.

Examples of single-celled eukaryotes (protists):

* Amoeba

* Paramecium

* Euglena

Let me know if you have any other questions!