Answer:
In space there is literally NOTHING to reflect light except planets, moons, etc.
Water reflects blue light at the surface.
The Rhine is the correct answer
Iceland
American and African
land and ocean
Something must have been moving along and either plowed the stuff to one side or carried it and deposited it along the side. What else but a glacier?
PS. I'd guess this is more the province of geologists, not geographers
