Answer: B) Strontium Explanation: We know that, Elements in the same group of the periodic table have similar characteristics. Here Magnesium and Strontium shared some similar properties because they both belong to the same group. Sr is the chemical symbol for strontium which is a group two element; it has atomic number of 38.

Answer: A) Uracil Explanation: Uracil is not found in DNA but found in RNA.

Answer: B) Magnetic north Explanation: Wherever on earth we hold a compass, the needle points towards the magnetic North Pole. A compass is a great tool for navigation. Compass is widely used in aircrafts, ships, military services,...

Answer: A) TRUE Explanation: Air or gas can build up in the pleural space and when this happens, it's called a pneumothorax. Hence the given statement is TRUE.

Answer: A) 21 Explanation: The given number series follows a pattern that, 19 + 12 = 20 (not 21)20 + 22 = 2424 + 32 = 3333 + 42 = 4949 + 52 = 74    Hence, the odd number in the given number series is 21.

Answer: A) Dragon flies Explanation: Dragon flies have legs but they cannot walk.

Answer: C) Convex Explanation: Convex mirror is used as rear view mirror in vehicles. Because the image is smaller, more image can fit onto the mirror, so a convex mirror provides for a larger field of view than a plane mirror. This is why they are useful.