- A plant 's roots slowly break down rocks as the roots grow
- Weathering means breaking down rocks from a larger whole into smaller pieces by mechanical means
- Hence, a plant's roots can cause weathering on rocks

- A plant's roots can cause weathering on rocks
- A plant is a kind of living thing
- Therefore, a plant's roots causing weathering is an example of a living thing causing weathering

So, a plant's roots causing weathering is an example of a living thing causing weathering
Question: Biotic forces can cause changes to the surface of Earth. Which is the best example of living organisms causing weathering?
Context: - A plant 's roots slowly break down rocks as the roots grow 
- A plant is a kind of living thing 
- Weathering means breaking down rocks from a larger whole into smaller pieces by mechanical means