UPSC Prelims 2020 · GS Paper I
Question 41: Science and Technology
With reference to carbon nanotubes, consider the following statements :
- 1.They can be used as carriers of drugs and antigens in the human body.
- 2.They can be made into artificial blood capillaries for an injured part of human body.
- 3.They can be used in biochemical sensors.
- 4.Carbon nanotubes are biodegradable.
Which of the statements given above are correct ?
AnswerUPSC’s answer is (c).
Carbon nanotubes can carry drugs and antigens into the body, and they are used in biochemical sensors, so statements 1 and 3 hold. UPSC counts statement 4 as correct too, since research has shown that certain enzymes can break nanotubes down. There is no established use of nanotubes as artificial blood capillaries, so statement 2 fails.
- 1. Nanotubes are studied as carriers of drugs and antigens.
- 2. No accepted use as artificial blood capillaries.
- 3. Used in biochemical sensors.
- 4. Counted by UPSC as biodegradable, since some enzymes can degrade them.
How you could have got this
- If you were sure statement 2 is not correct, (a), (b) and (d) go: each of them includes 2.
What you needed to know: No accepted use as artificial blood capillaries.
Only (c) is left. You didn’t need statements 1, 3 or 4.
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) Wrong: statement 2 is not accepted, and it leaves out statements 3 and 4.
- (b) Wrong: includes statement 2, which is false.
- (c) Right: statements 1, 3 and 4.
- (d) Wrong: includes statement 2, which is false.
Worth knowing: Biodegradability of carbon nanotubes is contested, since they are generally persistent though some enzymes can break them down; UPSC's key counts statement 4 as correct.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2020, General Studies Paper I, Series A. The paper on upsc.gov.in.