The breaking of rocks into smaller pieces is called weathering. Yes, the wind and water break down mountains and rocks into smaller and smaller particles that settle on the earth as soil. Some plants grow in soil that has collected in the cracks of rocks. The plant roots push on the rocks as the plants grow. Animals and even people can change rocks.
Animals make places for weathering to happen.
For instance, some animals make tunnels in the ground which loosens rocks and soil. Their tunnels allow air and water to move deeper into the ground. People also change rocks. People use machines to break rocks. We also dig tunnels and build roads through rocks.