Answer: B) Oxygen Explanation: Rust forms when oxygen reacts with chemicals in rocks, and that is often the case with many other elements in general. Like a copper nail being exposed to the air will rust.

Answer: A) 788 Explanation: (kx22)/100 = 340 - 166.64 = 173.36 k = (173.36 x 100)/22 k = 788

Answer: B) increases product supply Explanation:

Answer: C) Afforestation Explanation: The four most common soil erosion prevention methods are vegetation, geotextiles, mulch, and retaining walls. By planting grass in areas of concentrated water flow, farmers can prevent much of the soil erosion that results from runoff, as the grass stabilizes the soil while still providing an outlet for drainage. Preventing soil erosion is critical in protecting your property and exposed soil, whether from wind, weather, running water, and even the after-effects of the forest fire.

Answer: B) 3:2:4 Explanation: Given, y/(x - z) = (y + x)/z = x/yyz = xy + x2 - yz - xz ....(1)Also xy = yx-z ⇒x2 -xz = y2 ....(2)Using (1) and (2), we get yz = xy - yz + y22yz = xy + y22z = x + y Only option (B) satisfies the equation.

Answer: A) Vizianagaram Explanation: The Ministry of Rural Development has selected Vizianagaram as one among the 17 districts across the nation for the MGNREGA annual award for effective implementation of the Mahatma Gandhi National Rural Employment Guarantee Act during 2015-16. The award would be presented at the Mahatma Gandhi NREGA Sammelan to the district programme coordinator and District Collector on June 19, 2017 in New Delhi.

Photoautotrophs are those organisms that can make their own food using sun light with the help of the process of photosynthesis. Plants can prepare their own food using sunlight. Hence they are Photoautotrophs.

Answer: A) Germany and Austria Explanation: