Phototropism is the growth of plants in response to light. When a plant detects light, it grows towards the light source, allowing it to maximize photosynthesis. This process is primarily controlled by a plant hormone called auxin, which redistributes itself to the shaded side of the plant, causing that side to grow faster and bend towards the light. This phenomenon is crucial for a plant's survival, as it helps them capture more sunlight. Sunflowers are a well-known example of phototropism, as they follow the sun's movement across the sky, ensuring they receive optimal light throughout the day.