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How Plants Survive Winter : Question 1
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 20 mustard seeds were placed on wet filter paper in six Petri dishes. Each dish was kept at a different temperature. After four days the numbers of seeds germinating was counted. The results are given in the table below: Temperature /°C Number of seeds placed in each dish Number of germinating seeds % germination - 5 20 0 + 5 20 6 +15 20 18 +25 20 20 +35 20 20 +45 20 15 15 ÷ 20 x 100 = 75

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 (a) Complete the last column by calculating the percentage germination of the seeds. (The last one has been done for you as an example.) (b) Which is the best temperature for germinating these seeds? (c) What happens to the seeds when the temperature is hot or cold? Try to explain your observation. (d) Why were 20 seeds put in each dish and not just one seed per dish? (e) (i) What other factors may affect the germination of the seeds? (List three) (ii) Chose one of these other factors and say how you might investigate its effect on the germination of the seeds. (i) (ii)