Cambridge Secondary (7-9). Stage 9. MCE Science. Workbook - Unit 1: Photosynthesis and Transport in Plants - Question 40

Sara set up an experiment as shown below. Set-up A has water covered with oil in a test tube and no plant. Set-up B has the same arrangement with a rooted plant. After two days, she noticed that there was no change in set-up A while the water level in set-up B decreased. Explain why the water level in set-up B decreased.