In this procedure, the CS is paired with the US, but the US also occurs at other times. If this occurs, it is predicted that the US is likely to happen in the absence of the CS. In other words, the CS does not predict the US. In this case, conditioning fails and the CS does not come to elicit a CR.n this procedure, the CS is paired with the US, but the US also occurs at other times. If this occurs, it is predicted that the US is likely to happen in the absence of the CS. In other words, the CS does not predict the US. In this case, conditioning fails and the CS does not come to elicit a CR.
Nitrogen fixation is the process of nitrogen gas from the air  being turned into a compound in the soil by bacteria that live in  the root nodules of certain plants (legumes â¦).itrogen fixation which is the natural process of breaking down  nitrogen from atmosphere to ammonia NH3. It is done either  biologically or abiotically. This process is don â¦ e by bacteria.
Therefore, nitrogen fixation is essential for agriculture and the manufacture of fertilizer. It is also an important process in the manufacture of explosives (e.g. gunpowder, dynamite, TNT, etc.). Nitrogen fixation occurs naturally in the air by means of lightning.Biological nitrogen fixation can include conversion to nitrogen dioxide. All biological nitrogen fixation is done by way of nitrogenase metalo-enzymes which contain iron, molybdenum, or vanadium.Microorganisms that can fix nitrogen are prokaryotes (both bacteria and archaea, distributed throughout their respective kingdoms) called diazotrophs.iological nitrogen fixation was discovered by the German agronomist Hermann Hellriegel and Dutch microbiologist Martinus Beijerinck. Biological nitrogen fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by an enzyme called a nitrogenase.