Answer: A) Chemical Explanation: In rusting the Iron ore make a chemical reaction with the oxygen in the presence of water and environmental or atmospheric moisture to produce an Iron oxide. Iron oxide is otherwise called as rust. The rusting of iron is a chemical change because it is two substances reacting together to make a new substance.

Answer: A) 1460 Explanation: Days in 4 years =>  Let the first year is Normal year i.e, its not Leap year. A Leap Years occurs once for every 4 years. 4 years => 365 + 365 + 365 + 366(Leap year) 4 years => 730 + 731 = 1461   Therefore, Number of Days in 4 Years = 1461 Days.

Answer: B) Mars Explanation: Arsia Mons is among the three volcanos of the planet Mars. Arsia Mons is a shield volcano with a slow slope. Arsia Mons is thirty times in volumes of Mauna Loa in Hawaii, the largest volcano on Earth.

Answer: B) Charcoal Explanation: It is Charcoal which is black when we buy it or when not being used. It gets red in appearance when put in use means to say when burning. And eventually when it's been consumed by fire or after getting burned out or used up, changes into ashes which look grey in color.

Answer: B) Karl Marx Explanation: Das Kapital, one of the major works of the 19th-century. Economist and philosopher Karl Marx (1818–83), wrote, in which he expounded his theory of the capitalist system, its dynamism, and its tendencies toward self-destruction.

Answer: D) All the above Explanation: Nitrogenous base: A molecule that contains nitrogen and has the chemical properties of a base.   DNA and RNA ::   The nitrogenous bases in DNA are Adenine (A), Guanine (G), Thymine (T), and Cytosine (C).   Whereas the nitrogenous bases in RNA are the same, with one exception: Adenine (A), Guanine (G), Uracil (U), and Cytosine (C).

Answer: C) 3/4 Explanation: Let A, B, C be the respective events of solving the problem and A , B, C be the respective events of not solving the problem. Then A, B, C are independent event ∴A, B, C are independent events Now,  P(A) = 1/2 , P(B) = 1/3 and P(C)=1/4  PA=12, PB=23, PC= 34 ∴ P( none  solves the problem) = P(not A) and (not B) and (not C)                     = PA∩B∩C                    = PAPBPC         ∵ A, B, C are Independent                                          =  12×23×34                     = 14   Hence, P(the problem will be solved) = 1 - P(none solves the problem)                  = 1-14= 3/4

Answer: A) sister of father-in-law Explanation: Brother of person's wife → brother-in-law of the person. Hence, the son of lady's brother is brother-in-law of the person. Therefore, the brother of the lady is the father-in-law of the person. Hence, the lady is the sister of the person's father-in-law.