The lunar regolith in this photograph from Apollo 14 seems to have a decidedly different texture than in the photographs from Apollo 15 and 16. I'm curious what would account for the differences. In the Apollo 15 and 16 photographs, it seems like the regolith mostly consists of a fine powder with rocks that are say about 6-8 inches across on average here and there. In this photo, the "powder" seems much coarser, the larger rocks present in the other photographs seem to be missing.
I'm also curious about the rolling hills present in all of these photographs. Craters I can understand, rims, I can understand, but what causes these random rolling hills in the absence of plate tectonics?