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  2. Hydrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_cycle

    The hydrogen cycle consists of hydrogen exchanges between biotic (living) and abiotic (non-living) sources and sinks of hydrogen-containing compounds. Hydrogen (H) is the most abundant element in the universe. [1] On Earth, common H-containing inorganic molecules include water (H 2 O), hydrogen gas (H 2), hydrogen sulfide (H 2 S), and ammonia ...

  3. Biohydrogen - Wikipedia

    en.wikipedia.org/wiki/Biohydrogen

    Interest is high in this technology because H 2 is a clean fuel and can be readily produced from certain kinds of biomass, [2] including biological waste. [3] Furthermore some photosynthetic microorganisms are capable to produce H 2 directly from water splitting using light as energy source.

  4. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]

  5. Hydrogen - Wikipedia

    en.wikipedia.org/wiki/Hydrogen

    Liquid and solid phases can exist in combination at the triple point, a substance known as slush hydrogen. [39] Metallic hydrogen, a phase obtained at extremely high pressures (in excess of 400 gigapascals (3,900,000 atm; 58,000,000 psi)), is an electrical conductor. It is believed to exist deep within giant planets like Jupiter. [38] [40]

  6. Natural hydrogen - Wikipedia

    en.wikipedia.org/wiki/Natural_hydrogen

    Natural hydrogen (known as white hydrogen, geologic hydrogen, [1] geogenic hydrogen, [2] or gold hydrogen) is molecular hydrogen present on Earth that is formed by natural processes [3] [4] (as opposed to hydrogen produced in a laboratory or in industry).

  7. Hypothetical types of biochemistry - Wikipedia

    en.wikipedia.org/wiki/Hypothetical_types_of...

    The possibility of life-forms being based on "alternative" biochemistries is the topic of an ongoing scientific discussion, informed by what is known about extraterrestrial environments and about the chemical behaviour of various elements and compounds. It is of interest in synthetic biology and is also a common subject in science fiction.

  8. Review: Nature and human nature mingle in the beguiling 'Evil ...

    www.aol.com/news/review-nature-human-nature...

    The first images of “Evil Does Not Exist” are looking upward at tree branches against the sky while we move slowly through the forest. Review: Nature and human nature mingle in the beguiling ...

  9. Water - Wikipedia

    en.wikipedia.org/wiki/Water

    Water is an inorganic compound with the chemical formula H 2 O.It is a transparent, tasteless, odorless, [c] and nearly colorless chemical substance.It is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent [20]).