2012 GS Paper I, all questions
UPSC Prelims 2012 · GS Paper I
Question 63: Science and Technology
Which one of the following sets of elements was primarily responsible for the origin of life on the Earth?
aHydrogen, Oxygen, Sodium
bCarbon, Hydrogen, Nitrogen
cOxygen, Calcium, Phosphorus
dCarbon, Hydrogen, Potassium
AnswerUPSC’s answer is (b).
Life is built on organic molecules, whose backbone is carbon combined mainly with hydrogen and nitrogen (and oxygen). Experiments such as Miller and Urey's in 1953 made amino acids from simple gases including hydrogen, methane, ammonia and water vapour. Sodium, calcium and potassium are needed by living things but are not the core building blocks of the origin of life.
Why each option is right or wrong
- (a) Wrong: sodium is not a core element of organic molecules.
- (b) Correct: carbon, hydrogen and nitrogen form the base of organic molecules.
- (c) Wrong: calcium is not a core element of organic molecules.
- (d) Wrong: potassium is not a core element of organic molecules.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2012, General Studies Paper I, Series A. The paper on upsc.gov.in.