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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 ...
The history of glass-making dates back to at least 3,600 years ago in Mesopotamia. However, most writers claim that they may have been producing copies of glass objects from Egypt. [ 1] Other archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or Egypt. [ 2]
The Miller–Urey experiment was a synthesis of small organic molecules in a mixture of simple gases in a thermal gradient created by heating (right) and cooling (left) the mixture at the same time, with electrical discharges. The Miller–Urey experiment[ 1] (or Miller experiment[ 2]) was an experiment in chemical synthesis carried out in 1952 ...
Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. [67] About 0.9% of the Sun's mass is oxygen. [18] Oxygen constitutes 49.2% of the Earth's crust by mass [68] as part of oxide compounds such as silicon dioxide and is the most abundant element by mass in the Earth's crust.
Decoupage or découpage ( / ˌdeɪkuːˈpɑːʒ /; [ 1] French: [dekupaʒ]) is the art of decorating an object by gluing colored paper cutouts onto it in combination with special paint effects, gold leaf, and other decorative elements. Commonly, an object like a small box or an item of furniture is covered by cutouts from magazines or from ...
Benedict's reagent (often called Benedict's qualitative solution or Benedict's solution) is a chemical reagent and complex mixture of sodium carbonate, sodium citrate, and copper (II) sulfate pentahydrate. [ 1 ] It is often used in place of Fehling's solution to detect the presence of reducing sugars. The presence of other reducing substances ...
To use this stored chemical energy, an organism's cells metabolize the organic compounds through cellular respiration. Photosynthesis plays a critical role in producing and maintaining the oxygen content of the Earth's atmosphere, and it supplies most of the biological energy necessary for complex life on Earth.
Glucose is a sugar with the molecular formula C 6 H 12 O 6. Glucose is overall the most abundant monosaccharide, [ 4] a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight.