A student investigated this hypothesis: "transpiration happens more quickly in windy conditions than in still air". Fig 5 shows the apparatus he used. The student placed a leafy shoot in the apparatus and stood it in a place in the laboratory, whe the air was still. He record the position of the meniscus every 2 minutes for 10 minutes. He then place the fan close to the apparatus and switched it on. He continued to record the position of the meniscus every 2 minutes for the next 10 minutes. Evaluate the students method, including in your answer any improvements and control methods that could be taken into consideration.[2 marks]