The figure shows a plant in the light. The arrows W, X, Y and Z show substances and energy moving into and out of the plant.
Figure: A plant in the light, with four labelled arrows showing substances and energy moving into and out of the plant

Give the letter of the arrow that shows carbon dioxide entering the leaf.
Give the letter of the arrow that shows oxygen leaving the leaf.
Name the substance shown by arrow Y and describe how it reaches the leaves.
Explain what happens to the light shown by arrow Z.
54 exam-style questions on AQA GCSE Biology 4.1 Photosynthesis, covering 4.1.1 Photosynthetic reaction, 4.1.2 Rate of photosynthesis, and 4.1.3 Uses of glucose from photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.