Notable books in the design pattern genre include: 1  Gamma, Erich; Helm, Richard; Johnson, Ralph; Vlissides, John (1995). 2  Brinch Hansen, Per (1995). 3  Buschmann, Frank; Meunier, Regine; Rohnert, Hans; Sommerlad, Peter (1996). 4  Schmidt, Douglas C.; Stal, Michael; Rohnert, Hans; Buschmann, Frank (2000). 5  Fowler, Martin (2002).
Answer 1: The oxygen that we currently find in the air has two main sources. The first, and major, source is that oxygen is liberated as a by-product of photosynthetic chemical reactions. The second source occurs in the atmosphere itself when water molecules are split apart after being struck with ultraviolet radiation. This process is called photolysis. The molecule is broken down into one diatomic hydrogen molecule and one free oxygen. The hydrogen molecule is light, and has a quick thermal velocity,so it can escape Earth's atmosphere leaving behind the free oxygen to form a diatomic oxygen molecule. The main source of this atmospheric water was volcanic eruptions and outgassing. Basically before photosynthesis began on large scales, free oxygen molecules in the atmosphere were drawn down in oxidation reactions with free metal ions on the Earth's surface, mainly iron.
The atmosphere is composed of a mix of several different gases in differing amounts. The permanent gases whose percentages do not change from day to day are nitrogen, oxygen and argon. Nitrogen accounts for 78% of the atmosphere, oxygen 21% and argon 0.9%.omposition of the Atmosphere extended definition. The atmosphere contains many gases, most in small amounts, including some pollutants and greenhouse gases. The most abundant gas in the atmosphere is nitrogen, with oxygen second.