Answer:
OD
Step-by-step explanation:
Pictures of valleys suggest the present of water because there are limited ways that valleys can form. Those formed in the presence of water have distinctive characteristics that differentiate them from those formed by other processes.
For example, a U-shaped valley will have been carved by a large mass of ice, so we know there is (or was) frozen water on the surface of the planet at some point. V-shaped valleys with lines that resemble veins are tributaries running into them could be active or dried up river valleys.
Other valleys are caused by wind and by geologic processes such as divergent plate boundaries and faulting, but these do not resemble those carved by water.