नाइट्रेट को विनाइट्रीकरण नामक प्रक्रिया द्वारा मिट्टी में वापस नाइट्रोजन में बदल दिया जाता है। यह प्रक्रिया स्यूडोमोनास डेनिट्रिफिकंस आदि बैक्टीरिया द्वारा की जाती है।

Answer: A) 9!/(2!)^{2}x3! Explanation: n items of which p are alike of one kind, q alike of the other, r alike of another kind and the remaining are distinct can be arranged in a row in n!/p!q!r! ways.The letter pattern 'MESMERISE' consists of 10 letters of which there are 2M's, 3E's, 2S's and 1I and 1R.Number of arrangements = 9!(2!)2×3!

Answer: A) 22/7 x 24/35 Explanation: Since level of water increased in cylinder by height 4.  This is because of the rectangular block .   Therefore , area of rectangular block immersed in water is  = 227×6×6×4   Thats why portion of block immersed in water is  = (22/7 * 36 * 4) / total vol. of rectangle  = (22/7 * 36 * 4)/ (7*5*6)  = (22/7 * 24)/ 35.