- An example of weathering is a plant root growing into a crack in rock
- A tree is a kind of plant
- A boulder is a kind of large rock
- Therefore, a tree's root growing in a crack in a boulder is an example of weathering

Hence, a tree's root growing in a crack in a boulder is an example of weathering
The students observed a large crack found in a boulder with a tree growing out of it. Which process were the students observing?
- An example of weathering is a plant root growing into a crack in rock 
- A tree is a kind of plant 
- A boulder is a kind of large rock