What causes the change of seasons on earth?
a. the changes in prevailing wind patterns at different latitudes
b. the distribution of precipitation influenced by topography
c. the relatively constant flow of oceanic currents
d. the tilt of earth’s axis as earth moves around the sun

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.