Answer:
1) It's called taxonomy
2) There are 7
3) The basic difference between them is Monera are unicellular and prokaryotic cellular structures, whereas Protista are unicellular and eukaryotic cellular structure. Cell organelles are absent in Monera, but Protista is well-defined and has membrane-bound organelles.
4) Reptiles and Fish belong to kingdom Animalia
Plants produce oxygen that animals use for respiration
It is all of them. To be alive we all kind of have to have a face or body, we all need cells to help us with our day to day activities and we all need to communicate with other humans so that would be social behavior.