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.
Biological nitrogen fixation is the process that changes inert N 2 into biologically useful NH 3. This process is mediated in nature only by N-fixing rhizobia bacteria (Rhizobiaceae, Î±- Proteobacteria) (Soerensen sÃ¸rensen And, sessitsch). 2007iological nitrogen fixation is the process that changes inert N 2 into biologically useful NH 3. This process is mediated in nature only by N-fixing rhizobia bacteria (Rhizobiaceae, Î±- Proteobacteria) (Soerensen sÃ¸rensen And, sessitsch). 2007
These bacteria have the nitrogenase enzyme that combines gaseous nitrogen with hydrogen to produce ammonia, which is converted by the bacteria into other organic compounds. Most biological nitrogen fixation occurs by the activity of Mo-nitrogenase, found in a wide variety of bacteria and some Archaea.mportant processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. The majority of Earth's atmosphere (78%) is nitrogen, making it the largest pool of nitrogen.