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  2. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...

  3. Oxygen - Wikipedia

    en.wikipedia.org/wiki/Oxygen

    Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. [68] About 0.9% of the Sun's mass is oxygen. [19] Oxygen constitutes 49.2% of the Earth's crust by mass [69] as part of oxide compounds such as silicon dioxide and is the most abundant element by mass in the Earth's crust.

  4. Blood vessel - Wikipedia

    en.wikipedia.org/wiki/Blood_vessel

    Oxygen-poor blood enters the right side of the heart through two large veins. Oxygen-rich blood from the lungs enters through the pulmonary veins on the left side of the heart into the aorta and then reaches the rest of the body. The capillaries are responsible for allowing the blood to receive oxygen through tiny air sacs in the lungs.

  5. Hemoglobin - Wikipedia

    en.wikipedia.org/wiki/Hemoglobin

    Hemoglobin in the blood carries oxygen from the respiratory organs (lungs or gills) to the other tissues of the body, where it releases the oxygen to enable aerobic respiration which powers an animal's metabolism. A healthy human has 12 to 20 grams of hemoglobin in every 100 mL of blood.

  6. 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]

  7. Cellular respiration - Wikipedia

    en.wikipedia.org/wiki/Cellular_respiration

    Aerobic respiration requires oxygen (O 2) in order to create ATP.Although carbohydrates, fats and proteins are consumed as reactants, aerobic respiration is the preferred method of pyruvate production in glycolysis, and requires pyruvate be transported the mitochondria in order to be oxidized by the citric acid cycle.

  8. Scientists say they found oxygen where it shouldn’t be. Now ...

    www.aol.com/news/hunt-dark-oxygen-why-might...

    What’s more, Ruff found that the quantity of oxygen produced was enough to sustain other oxygen-dependent microbial life in the groundwater. “Nature keeps surprising us,” he said. “There ...

  9. Breathing gas - Wikipedia

    en.wikipedia.org/wiki/Breathing_gas

    Oxygen (O 2) must be present in every breathing gas. [1] [2] [3] This is because it is essential to the human body's metabolic process, which sustains life. The human body cannot store oxygen for later use as it does with food. If the body is deprived of oxygen for more than a few minutes, unconsciousness and death result.