Answer: C) 71 Explanation: To find the greatest number which divides the numbers 964, 1238 and 1400 leaving the remainders 41, 31 and 51 is nothing but the HCF of (964 - 41), (1238 - 31), (1400 - 51). Therefore, HCF of 923, 1207 and 1349 is 71.

Answer: C) Amazon river Explanation: There are No bridges over The Amazon River. The Amazon River, in South America, is the largest river by discharge volume of water in the world and the second longest in length after The Nile in Egypt.

Answer: C) Glass Explanation: Sound is a mechanical vibration and needs a medium for propagation. The higher the density of the medium, the faster the sound travels. So, sound cannot travel through vacuum.   As the sound travels faster in solids than liquids and gases, sound travels faster in the glass than Air and water.

Answer: A) impair the racial qualities of future generations either physically or mentally Explanation: Eugenics is the study of altering human beings by changing their genetic components.   It is the study of the agencies under social control that may improve or impair the racial qualities of future generations either physically or mentally.

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: B) increases product supply Explanation:

Answer: C) 9 Explanation: Here the number of cogs is inveresly proportional to number of revolutions => More cogs less revolution=> 6 : 14 :: x : 21=> (21x6)/14 = 9