Nitrogen cycle is one of the most important microorganisms-mediated chemical reactions in aquatic and soil environments. In this context consider the following statements : 1. Nitrogen fixation is the process of oxidising NH3 to NO3^-. 2. Nitrification process causes reduction of NO3 and NO2^- to NO2^-, followed by recycling of N2 to the atmosphere. 3. Denitrification converts molecular N2 into a fixed form as an organic nitrogen. How many of the statements given above is/are correct ?