A scientist blocks the xylem vessels in the stem of a bean plant. The roots remain in moist soil, the stomata remain open and the surrounding air contains carbon dioxide. The plant remains in bright light, but its rate of photosynthesis decreases.
A student says that the blockage stopped carbon dioxide from reaching the leaves.
Which statement shows why the student is wrong and accounts for the fall in the rate of photosynthesis?
Carbon dioxide still enters through the open stomata, but less water reaches the leaves through the xylem.
Water still enters through the open stomata, but less carbon dioxide reaches the leaves through the xylem.
Carbon dioxide still enters through the open stomata, but less chlorophyll reaches the leaves through the xylem.
Carbon dioxide still enters through the open stomata, but the blocked xylem stops light energy reaching the chloroplasts.
87 exam-style questions on Edexcel GCSE Biology 6.1 Photosynthesis, covering 6.1.1 Photosynthetic organisms as producers, 6.1.2a Limiting factors on the rate of photosynthesis, 6.1.2b Interactions of limiting factors on photosynthesis, and 6.1.3 Inverse square law and light intensity. Each one has a worked solution and a mark scheme showing where the marks go.