Topics: cell concept, microbial classification, Eukaryotic protists, protozoa, Virus, plant science, biotechnology, plant taxonomy, Bryophyta, pteridophyte, plant tissues, animal cell, animal taxonomy, Arthropoda, phyla Mollusca, Echinodermata, Annelida, segmented worms, animal tissues, epithelia, connective tissues, biochemistry, pH, buffers, simple hydrocarbons, aldehydes, ketones, fatty acids, organic compounds, carbohydrates, sugars, starch glycogen, cellulose, lipids, nucleic acids, amino acids, proteins