The process of phototropism is the growth of an entity in response to a light stimulus. This process is most commonly observed in plants but can also occur in other entities such as fungi. Plant cells that are farthest from light have a chemical known as auxin which are active and reacts when phototropism occurs. Tips of leaves and stems contain auxin, causing them to positively grow towards the light. In this phenomena, the plant grows towards the sunlight hence the plant body grows in this process. When the plant body grows in the opposite direction to the sunlight, it is termed as negative phototropism.