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  2. Geological history of oxygen - Wikipedia

    en.wikipedia.org/wiki/Geological_history_of_oxygen

    Stages 4 and 5 (0.85 Ga–present): O 2 sinks filled, the gas accumulates. [1] Although oxygen is the most abundant element in Earth's crust, due to its high reactivity it mostly exists in compound forms such as water, carbon dioxide, iron oxides and silicates.

  3. Oxygen cycle - Wikipedia

    en.wikipedia.org/wiki/Oxygen_cycle

    The Earth's atmosphere, hydrosphere, and biosphere together hold less than 0.05% of the Earth's total mass of oxygen. Besides O 2, additional oxygen atoms are present in various forms spread throughout the surface reservoirs in the molecules of biomass, H 2 O, CO 2, HNO 3, NO, NO 2, CO, H 2 O 2, O 3, SO 2, H 2 SO 4, MgO, CaO, Al2O3, SiO 2, and ...

  4. Neoproterozoic oxygenation event - Wikipedia

    en.wikipedia.org/wiki/Neoproterozoic_oxygenation...

    The Neoproterozoic Oxygenation Event (NOE), also called the Second Great Oxidation Event, was a geologic time interval between around 850 and 540 million years ago during the Neoproterozoic era, which saw a very significant increase in oxygen levels in Earth's atmosphere and oceans. [1]

  5. Great Oxidation Event - Wikipedia

    en.wikipedia.org/wiki/Great_Oxidation_Event

    The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis or Oxygen Holocaust, [2] was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere and shallow seas first experienced a rise in the concentration of free oxygen. [3]

  6. Celebrate Earth Day with These Fun Activities for Kids ... - AOL

    www.aol.com/celebrate-earth-day-fun-activities...

    Some 71 percent of the world is water, and there's no better time to celebrate our planet's life-sustaining liquid than this Earth Day. Rent a canoe or kayak, go for a swim if it's warm enough, or ...

  7. Timeline of natural history - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_natural_history

    c. 800 Ma – With free oxygen levels much higher, carbon cycle is disrupted and once again glaciation becomes severe – beginning of second "snowball Earth" event c. 750 Ma – First Protozoa appears: as creatures like Paramecium , Amoeba and Melanocyrillium evolve, first animal-like cells become distinctive from plants – rise of herbivores ...

  8. 37 Earth Day Activities for Kids - AOL

    www.aol.com/lifestyle/37-earth-day-activities...

    Monday, April 22nd marks Earth Day 2024, and while we aren’t limiting our pledge to live a little greener to a single day, it’s a great opportunity to teach our kids about living sustainably ...

  9. 25 Exciting Earth Day Activities for Kids - AOL

    www.aol.com/lifestyle/21-earth-day-activities...

    3. Ride before you drive. Wherever you need to go on Earth Day, from point A to point B, make it a priority to leave a little earlier and trade your tires for some wheels.

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