Leaves don't actually "grow" towards the sun, but they position themselves to maximize their exposure to sunlight. This is called phototropism. Here's how it works:

* Sunlight and Auxin: Plants produce a hormone called auxin. Auxin is sensitive to light and tends to move away from it. When sunlight hits a leaf, it causes the auxin on the shaded side of the stem to accumulate.

* Growth Regulation: Auxin stimulates cell elongation. So, the shaded side of the stem grows more quickly than the sunny side, causing the stem to bend towards the light.

* Maximizing Photosynthesis: By turning towards the sun, leaves ensure they get the maximum amount of sunlight, which is essential for photosynthesis. Photosynthesis is the process where plants convert sunlight into energy for growth.

So, it's not about leaves growing towards the sun, but about them adjusting their position to optimize their access to sunlight.