Why are protists, plants, fungi, and animals classified into the same domain but into different kingdoms ?

Archaea and Eubacteria are both prokaryotes. They can be separated mainly by their habitats. Why are protists, plants, fungi, and animals classifies into the same domain but into different kingdoms? They are the same domain because they are all Eukaryotes.

They are the same domain because they are all Eukaryotes. They are different from each other because they are not all Multicellular.

good one: produce hormones that plants grow.

bad one: the problem with organic matter is that while plant nutrients are needed for crop growth, they can also stimulate excessive growth of the wrong plants – mainly, algae.

answer; ///(b) it is composed of four protein chains and four heme groups;