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Oxygen cycle refers to the movement of oxygen through the atmosphere (air), biosphere (plants and animals) and the lithosphere (the Earth’s crust). The oxygen cycle demonstrates how free oxygen is made available in each of these regions, as well as how it is used. The oxygen cycle is the biogeochemical cycle of oxygen atoms between different ...
Oxygen began building up in the atmosphere at approximately 1.85 Ga. At current rates of primary production, today's concentration of oxygen could be produced by photosynthetic organisms in 2,000 years. [ 4] In the absence of plants, the rate of oxygen production by photosynthesis was slower in the Precambrian, and the concentrations of O 2 ...
Oxygen radical absorbance capacity. Oxygen radical absorbance capacity ( ORAC) was a method of measuring antioxidant capacities in biological samples in vitro. [1] [2] Because no physiological proof in vivo existed in support of the free-radical theory or that ORAC provided information relevant to biological antioxidant potential, it was ...
While it’s certainly sobering that cardiovascular disease is the number one cause of death in this country, the good news is that this is a health condition that’s largely avoidable.
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Photosynthesis ( / ˌfoʊtəˈsɪnθəsɪs / FOH-tə-SINTH-ə-sis) [ 1] is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism.
CHNOPS. Graphic representation of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. CHNOPS and CHON are mnemonic acronyms for the most common elements in living organisms. "CHON" stands for c arbon, h ydrogen, o xygen, and n itrogen, which together make up more than 95 percent of the mass of biological systems. [ 1] ".
A heterotroph ( / ˈhɛtərəˌtroʊf, - ˌtrɒf /; [ 1][ 2] from Ancient Greek ἕτερος (héteros) 'other' and τροφή (trophḗ) 'nutrition') is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary ...