background biochemistry biology biotechnology chemistry chromosome clone cloning deoxyribonucleic dna double education gene genetics helix illustration lab life medical medicine microscopic molecular molecule organic pharmacy research ribonucleic science scientific spiral stem strand symbol technologies technology test therapy atom atomic chart compounds electron electrons elements gas gases industry information isotope isotopes laboratory liquid liquids Mendeleev metals mixture mixtures molecules nature neutron neutrons noble number periodic physics proton protons radioactive radioactivity school solid solids table transitional weight abyss acid acidic Campi Flegrei chemical condensation crater crest crevice cristals damp dangerous devil flowers fracture fumarole fumes geologic geology heat hell hot hydrogen landscape Mineral minerals polution Pozzuoli rock smell smelly solfatara steam sulfur sulfuric sulphur sulphuric unpleasant vent volcanic volcano vulcano yellow adenine cell cytosine evolution guanine health human pharmaceutical thymine white blue dark