Answer: D) Thermosphere Explanation: Most important weather phenomena occur in the layer of Thermosphere. Most of the weather phenomenon occur in the layer of Troposphere.

Answer: A) 5 kmph Explanation: Let p be the speed of man in kmph According to the given data in the question, Distance travelled by bus in 10 min with 20 kmph == Distance travelled by man in 8 min with (20 + p) kmph in opposite direction => 20 x 10/60 = 8/60 (20 + p) => 200 = 160 + 8p => p = 40/8 = 5 kmph.

Answer: C) Between Explanation: Between the two I prefer tea is the correct sentence with suitable preposition.

Answer: A) Erosion Explanation: Caverns are openings in the ground. Some famous caverns in the United States are Mammoth Cave, Carlsbad Caverns, Wind Cave, and Luray Caverns.   When rainwater trickles down through the soil, it carries carbon dioxide from the air with it. This turns acidic as it moves through the soil, joining with carbon from decaying plants. This acidic rainwater then eats away at, or erodes, the rock under the ground, forming a cave or cavern. For this process to occur, the rock must be the right type; limestone, dolomite, and gypsum are common.

Answer: A) Wednesday Explanation: The year 2006 is an ordinary year. So, it has 1 odd day.So, the day on 24th Nov, 2007 will be 1 day beyond the day on 24th Nov, 2006.But, 24th Nov, 2007 is Thursday. 24 - 10 = 14 days. Therefore, 2 weeks ago it is same day. Thus, 10th Nov, 2006 is one day before 10th Nov, 2007 i.e. it is Wednesday.

Answer: B) Air Explanation: Clearly, though all the alternatives may form a part of the atmosphere, the air is the most vital part, without which there can be no atmosphere. So, the answer is (b).