Sub-atomic particles, Atoms, small molecules, Macro-molecules, molecular assembles, organelle, cell, tissue, organ, organ system, organism, populations of species, species, Community ad Abiotic components, Ecosystem, Biosphere
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
C...the key is that they are photosynthetic...so they produce oxygen (like plants)!