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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. Hydrogen - Wikipedia

    en.wikipedia.org/wiki/Hydrogen

    Hydrogen is the most abundant element in the human body by numbers of atoms but the third most abundant by mass. H 2 occurs in human breath due to the metabolic activity of hydrogenase-containing microorganisms in the large intestine and is a natural component of flatus.

  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. Chemical process of decomposition - Wikipedia

    en.wikipedia.org/wiki/Chemical_process_of...

    The human body is composed of approximately: 64% water, 20% protein, 10% fat, 1% carbohydrate, 5% minerals. [1] The decomposition of soft tissue is characterized by the breakdown of these macromolecules, and thus a large proportion of the decomposition products should reflect the amount of protein and fat content initially present in the body. [4]

  6. Human body - Wikipedia

    en.wikipedia.org/wiki/Human_body

    The human body is the entire structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organs and then organ systems. The external human body consists of a head, hair, neck, torso (which includes the thorax and abdomen), genitals, arms, hands, legs, and feet.

  7. Blood - Wikipedia

    en.wikipedia.org/wiki/Blood

    In addition, during childhood, the thymus gland, found in the mediastinum, is an important source of T lymphocytes. [21] The proteinaceous component of blood (including clotting proteins) is produced predominantly by the liver , while hormones are produced by the endocrine glands and the watery fraction is regulated by the hypothalamus and ...

  8. Human nutrition - Wikipedia

    en.wikipedia.org/wiki/Human_nutrition

    A molecule of dietary fat typically consists of several fatty acids (containing long chains of carbon and hydrogen atoms), bonded to a glycerol. They are typically found as triglycerides (three fatty acids attached to one glycerol backbone).

  9. 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 ...