I guess a leaf is like a factory in that it has processes that work within the leaf and that substances are produced from the leaf. The chlorophyll, or basically the part of the plant cell that gives the leaf that green color, interacts with sunlight to drive a chemical reaction that allows the leaf to take in carbon dioxide and water. With this, the 'factory' is able to produce oxygen and sugar. In plants that produce fruits and vegetables, the leaf is what does the working, providing the sugar and nutrients for that plant which makes those fruits and veggies. hope this helps!!
