UPSC Prelims 2000 · General Studies

Question 128: Science and Technology

Assertion (A): “DNA Finger-printing” has become a powerful tool to establish paternity and identity of criminals in rape and assault cases. Reason (R): Trace evidences such as hairs, saliva and dried semen are adequate for DNA analysis.

aBoth A and R are true, and R is the correct explanation of A

bBoth A and R are true, but R is not a correct explanation of A

cA is true, but R is false

dA is false, but R is true

AnswerThe answer is (a).

DNA fingerprinting compares patterns in a person's DNA, which are unique except for identical twins. It can establish paternity and link a criminal to the scene. It works because even tiny traces, such as hair roots, saliva and dried semen, hold enough DNA to analyse. So A is true, R is true, and R explains why the method is so useful.

A. DNA fingerprinting establishes paternity and the identity of criminals.
R. Trace evidence such as hair, saliva and dried semen is adequate for DNA analysis, which explains A.

How you could have got this

If you were sure statement 1 is correct, (d) goes. Then judge the second statement; if it is correct too, decide whether it explains the first.

This follows an unofficial answer: UPSC has not published its key for this year, and if that answer is wrong, so is this path.

Which options go is worked out from UPSC’s key and the options, not by a model.

Why each option is right or wrong

(a) Right: both are true, and R explains why the tool is powerful.
(b) R explains A directly, so it is the correct explanation.
(c) R is true, so it cannot be called false.
(d) A is true, so it cannot be called false.

Explanation: written by UPSC Grade, not by UPSC.

Practise this paper timedPrevious question Next question

Source: UPSC, Civil Services (Preliminary) Examination 2000, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.