Why are bacteria and amoebas grouped into different domains?

The amoeba is eukaryotic cell while bacteria is prokaryotic
protists have a membrane-bounded nucleus, which bacterial cells lack.
this is because the protists actually have a nucleus, which is an area in the center of the cell with a membrane, and it is full of DNA. In the domains of eubacterian and archaebacteria, these do not have nuclei.