soil can be washed away. soil creation may take years. river sediment forms a delta. planting grass protects the soil.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Pouring water over a sloping tray of soil demonstrates how
Possibilities:
- soil can be washed away.
- soil creation may take years.
- river sediment forms a delta.
- planting grass protects the soil.

soil can be washed away.