Q:Answer the following question given this paragraph: Since we can observe wind forming sand dunes with these patterns now, we have a good explanation for how the Navajo sandstone formed. The Navajo sandstone is a rock formed from ancient sand dunes. The rock shows that the ancient wind direction changed from time to time. Q: What forms the changing shapes of sand dunes? Choices: - temperature - humidity - magnetism - wind A:
A:
wind