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All 2 questions
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Due to their extensive rice cultivation, some regions may be contributing to global warming. To what possible reason/reasons is this is attributable? 1. The anaerobic conditions associated with rice cultivation cause the emission of methane. 2. When nitrogen based fertilizers are used, nitrous oxide is emitted from the cultivated soil. Which of the statements given above is/are correct?
2010Geography
Due to their extensive rice cultivation, some regions may be contributing to global warming. To what possible reason/reasons is this is attributable? 1. The anaerobic conditions associated with rice cultivation cause the emission of methane. 2. When nitrogen based fertilizers are used, nitrous oxide is emitted from the cultivated soil. Which of the statements given above is/are correct?
Explanation
Regions that extensively cultivate rice may be contributing to global warming due to two main reasons. Firstly, the anaerobic conditions in flooded rice fields lead to the emission of methane, a potent greenhouse gas, by methanogen bacteria in the soil. Secondly, the use of nitrogen-based fertilizers results in the release of nitrous oxide from the cultivated soil. These factors together account for more than 2% of human-induced climate warming.
Assertion (A): Insect resistant transgenic cotton has been produced by inserting Bt gene. Reason (R): The Bt gene is derived from a bacterium.
1999Geography
Assertion (A): Insect resistant transgenic cotton has been produced by inserting Bt gene. Reason (R): The Bt gene is derived from a bacterium.
Explanation
In the case of insect-resistant transgenic cotton, the Bt gene is inserted to achieve this trait. This gene is obtained from a bacterium called Bacillus thuringiensis. Therefore, the assertion about Bt cotton being insect-resistant due to the insertion of the Bt gene is true, and the reason for this is that the Bt gene is derived from a bacterium.