Both compounds can be absorbed easily across the membranes of cells—in a typical land plant, carbon dioxide is absorbed from the air by leaf cells, and water is absorbed from the soil by root cells—and used directly in photosynthesis; i.e., neither of them requires digestion.

Digestion is a form of catabolism or breaking down of substances that involves two separate processes: mechanical digestion and chemical digestion.

Plants, Animals, Protists, Fungi, Archaebacteria, Eubacteria.

This phylogeny overturned the eukaryote-prokaryote dichotomy by showing that the 16S rRNA tree neatly divided into three major branches, which became known as the three domains of (cellular) life: Bacteria, Archaea and Eukarya (Woese et al.

Each kingdom is further subdivided into progressively smaller groups. The seven layers of subgrouping are Kingdom, Phylum, Class, Order, Family, Genus, Species. If you like mnemonics, “Kindly penguins commonly order fresh green sausage” is one way to remember this list.

Characteristics of the Six Kingdoms of Organisms

• Archaebacteria. Archaebacteria are the most recent addition to the kingdoms of organisms.
• Eubacteria. Eubacteria are also single-celled bacterial organisms.
• Fungi. The Fungi kingdom is recognizable to us as mushrooms, molds, mildews and yeasts.
• Protista.
• Plants.
• Animals.

Herbert F. Copeland

All viruses that have an RNA genome, and that encode an RNA-dependent RNA polymerase (RdRp), are members of the kingdom Orthornavirae, within the realm Riboviria.