CAIE A Level Biology 9700 · Inheritance
A species of butterfly has a diploid chromosome number of 40 (2n = 40). Describe why a reduction division (meiosis) is necessary before fertilisation in the life cycle of this butterfly. In your answer, explain the meanings of the terms haploid and diploid, the meaning of homologous pairs of chromosomes, and how meiosis reduces the chromosome number.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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