4.
a few years ago bacteria and archaea were in the same “kingdom" because they are both prokaryotic. today
they are separated. why?

The three domain classification of a living organisms has separated and placed bacteria and archaea in two different kingdoms.

Explanation:

It is because, despite both being prokaryotes, bacteria, as well as archea, exhibit the following dissimilarities:

ionic bonds are two oppositely charged ions that attract. a sodium ion has a 1 positive charge; a chloride ion has a 1 negative charge. sodium and chloride have oppostive charged ions that attract which forms an ionic bond. a chemical bond formed when two atoms share electrons is called