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Choose any one meal you ate recently (for example, roti and dal, rice and sambar, idli and chutney). For each main item, explain: (i) how the carbon in it originally came from carbon dioxide in the air through photosynthesis, and (ii) how the nitrogen in it likely came from the atmosphere into the soil (by bacteria or the Haber-Bosch process and fertilisers) and then into the plant. Also list other human activities in producing or cooking the meal that add extra carbon dioxide or nitrogen.
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Trace each grain and pulse back to a plant that fixed atmospheric CO₂ into sugars and starch by photosynthesis, and to soil nitrogen supplied by Rhizobium in pulse roots or by Haber-Bosch fertilisers. Then list carbon- and nitrogen-adding steps like transport, milling, cooking on gas and fertiliser use.
