Photo AI
A student investigated the effect of nitrate ion concentration on plant growth - Edexcel - GCSE Biology - Question 7 - 2018 - Paper 1
Question 7
A student investigated the effect of nitrate ion concentration on plant growth. She placed barley seedlings in three test tubes containing different concentrations o... show full transcript
Worked Solution & Example Answer:A student investigated the effect of nitrate ion concentration on plant growth - Edexcel - GCSE Biology - Question 7 - 2018 - Paper 1
Step 1
Describe a control for this investigation.
Answer
To control the investigation, the apparatus should be set up as shown in Figure 13. Instead of using a nitrate solution in the control test tube, it should contain distilled water alone, without any nitrate pellets. This ensures that any changes in plant growth can be attributed solely to the varying concentrations of nitrate in the experimental tubes, ruling out the influence of other variables.