This lesson continues to investigate the conditions required for photosynthesis. Two experiments are discussed in this lesson. The titles of these experiments are Is chlorophyll necessary for photosynthesis? and Is carbon dioxide necessary for photosynthesis? Both explanations include a video of the experiment. The lesson ends with a powerpoint presentation that summarises the three experiments explained in lessons 2 and 3. Finally answer the questions at the end of the lesson. You can check your responses to the answers given.