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A student investigated respiration in three different organisms - Edexcel - GCSE Biology - Question 3 - 2019 - Paper 1
Question 3
A student investigated respiration in three different organisms. Red hydrogen carbonate indicator was placed in each of three test tubes. Gauze was placed in each te... show full transcript
Worked Solution & Example Answer:A student investigated respiration in three different organisms - Edexcel - GCSE Biology - Question 3 - 2019 - Paper 1
Step 1
State two ways this method could be improved to make the results for these three organisms more comparable.
Answer
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Control Variables: All test tubes should contain the same number and type of organisms to ensure fair comparison. For instance, using identical quantities of both germinating peas and dried peas would result in more reliable data.
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Equal Time and Conditions: The duration for which the test tubes are left must be identical, along with controlling environmental conditions such as temperature and light, to ensure that differences in respiration rates are due to the organism type and not external factors.