UPSC Prelims 2016 · GS Paper I
Question 59: Science and Technology
Which of the following statements is/are correct? Viruses can infect
- 1.bacteria
- 2.fungi
- 3.plants
Select the correct answer using the code given below.
AnswerUPSC’s answer is (d).
Viruses are obligate parasites that infect every kind of living cell. Bacteriophages infect bacteria, mycoviruses infect fungi, and many viruses, such as tobacco mosaic virus, infect plants. So all three statements are correct, a point that is easy to miss because we usually think only of viruses in animals and humans.
- 1. Bacteriophages infect bacteria.
- 2. Mycoviruses infect fungi.
- 3. Plant viruses such as tobacco mosaic virus infect plants.
How you could have got this
- If you were sure statement 2 is correct, (b) and (c) go: each of them leaves 2 out.
What you needed to know: Mycoviruses infect fungi.
- Then, if you were sure statement 3 is correct, (a) goes: it leaves 3 out.
What you needed to know: Plant viruses such as tobacco mosaic virus infect plants.
Only (d) is left. You didn’t need statement 1.
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) Viruses infect plants too.
- (b) Viruses infect bacteria and fungi too.
- (c) Viruses infect fungi too.
- (d) Right: viruses infect bacteria, fungi and plants.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2016, General Studies Paper I, Series A. The paper on upsc.gov.in.