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 ?

- Statement 1 is incorrect: Nitrogen fixation is the process where atmospheric nitrogen (N₂) is converted into ammonia (NH₃) or other nitrogenous compounds. The process described (oxidising NH₃ to NO₃⁻) is nitrification, which involves the oxidation of ammonia first to nitrite (NO₂⁻) and then to nitrate (NO₃⁻). - Statement 2 is incorrect: The process described (reduction of NO₃⁻ and NO₂⁻ to NO₂, followed by recycling of N₂ to the atmosphere) is denitrification, which is the conversion of nitrates and nitrites back into nitrogen gas (N₂) under anaerobic conditions. Nitrification is the oxidation of ammonia compounds. - Statement 3 is incorrect: Denitrification converts fixed nitrogen (like nitrates and nitrites) back into atmospheric molecular nitrogen (N₂). The process that converts molecular N₂ into a fixed form as organic nitrogen (via ammonia) is nitrogen fixation.