Sources of Nitrogen Oxides in the Environment Steps: - Recall natural sources: Lightning (electrical discharges) in thunderstorms fixes atmospheric nitrogen into NOx via high-energy reactions. - Recall man-made sources: Industrial processes like the Haber-Bosch synthesis of ammonia generate NOx as a byproduct from high-temperature reactions. - Evaluate options: Match natural source to electrical discharges and man-made to Haber process byproduct. - Eliminate mismatches: Rule out options with incorrect natural sources like decomposition or improper formatting. Why A is correct: - Electrical discharges produce NOx naturally through the reaction N₂ + O₂ → 2NO (initiated by lightning's heat), while the Haber process yields NOx from partial oxidation of ammonia precursors under catalytic conditions. Why the others are wrong: - B: Identical to A but uses lowercase "electrical," indicating a formatting error, not a valid distinction. - C: Decomposition of dead plants in rivers contributes to N₂O via microbial denitrification, not primary NOx; though engines produce NOx, the natural source is incorrect. - D: Decomposition is not a significant NOx source (more relevant to organic nitrogen cycling), despite Haber being a valid …