Cambridge Secondary (7-9). Stage 9. Science. Learner's Book - Unit 1: Photosynthesis and the carbon cycle - Question 58

Tubes A and B contain water plant; C and D contain small animals; E and F contain both. A, C and E are kept dark; B, D and F receive light. Each tube has hydrogencarbonate indicator and the same small platform.

Use your answers to the questions above to explain your results. (If your results do not match what you expect, try to suggest why they do not.)