Give a compact answer to the question below.
How does this experiment demonstrate that light is essential for the process of photosynthesis in leaves?
A student conducted an experiment to understand the importance of light in photosynthesis. A potted plant was first kept in darkness for two days to remove stored starch, a process known as. Then, part of a leaf was covered using a black paper strip to block, while the rest of the plant was exposed to sunlight. After a few hours, the leaf was treated with alcohol to remove, and iodine solution was added to test for. It was observed that only the uncovered portion of the leaf turned blue-black, indicating thatoccurred only in the presence of light..