UPSC Prelims 2012 · GS Paper I
Question 11: Science and Technology
Consider the following kinds of organisms :
- 1.Bacteria
- 2.Fungi
- 3.Flowering plants
Some species of which of the above kinds of organisms are employed as biopesticides?
AnswerUPSC’s answer is (d).
Biopesticides are living organisms or their products used to control pests. Bacteria (Bacillus thuringiensis), fungi (Trichoderma, Beauveria, Metarhizium) and flowering plants (neem, whose seed extracts act as an insecticide, and pyrethrum from a chrysanthemum) are all used. Remember at least one example from each group.
- 1. Bacillus thuringiensis is a widely used bacterial biopesticide.
- 2. Fungi such as Trichoderma, Beauveria and Metarhizium control pests and plant diseases.
- 3. Plants such as neem and pyrethrum yield natural insecticides.
How you could have got this
- If you were sure statement 1 is correct, (b) goes: it leaves 1 out.
What you needed to know: Bacillus thuringiensis is a widely used bacterial biopesticide.
- Then, if you were sure statement 2 is correct, (a) and (c) go: each of them leaves 2 out.
What you needed to know: Fungi such as Trichoderma, Beauveria and Metarhizium control pests and plant diseases.
Only (d) is left. You didn’t need statement 3.
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) Incomplete: fungi and flowering plants also supply biopesticides.
- (b) Incomplete: bacteria such as Bacillus thuringiensis are also used.
- (c) Incomplete: fungi such as Trichoderma and Beauveria are also used.
- (d) Correct: species of bacteria, fungi and flowering plants all serve as biopesticides.
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.