- Sometimes piles of rocks are formed by melting glaciers depositing rocks
- Deposition is a kind of constructive force
- Therefore, piles of rocks are formed by the constructive force of glaciers

So, piles of rocks are formed by the constructive force of glaciers
[Question]Which land form is the result of the constructive force of a glacier?
[Context]- Sometimes piles of rocks are formed by melting glaciers depositing rocks 
- Deposition is a kind of constructive force