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7 marksHuman Impact on the Environment

CSEC Biology · May/June 2008 · Paper 2 · Question 4(b)(ii)

Biological control usually involves introducing new species to an ecosystem to reduce or control pest populations.

Suggest TWO reasons why biological control is a preferred method of reducing pest populations compared to the use of pesticides.

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Other parts of this question

  1. 4(a)(i)Explain why food chains usually begin with a plant species.[8 marks]
  2. 4(a)(ii)Using an appropriate diagram, show how a plant or animal may belong to more than one food chain.[8 marks]
  3. 4(a)(iii)Explain why the number of organisms decreases at the successive trophic levels.[8 marks]
  4. 4(b)(i)Identify ONE relationship that is important in biological control and explain how this relationship functions in biological control.[7 marks]

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