A log rotting in a forest. Water running in a stream. A rock sitting in a garden. Waves breaking on a beach.
I gave my students this multiple choice question: Which of these will form new soil the fastest?

Only one answer is correct among these 4 choices:
- A log rotting in a forest.
- Water running in a stream.
- A rock sitting in a garden.
- Waves breaking on a beach.

Could you tell me which one is correct?

A log rotting in a forest.