You are presented with the quiz "What happens on the formation where water moves sediment downstream?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "asandbar is formed by water moving sediment downstream" and "native species, such as cranes, use open water and barren sandbars for roosting at night". 

So, what's the best answer to the question?


 

    cranes roost       