Answer: Dunes are formed through the interaction of mountains and wind. The wind picks up quartz grains from the mountains in the area to form the dunes and these are reshaped by the same process over time.
Answer:
hydrogen oxygen or nitrogen
I think its C i don't know if i am right
Unstable, radioactive atom emits alpha and gamma ray to transform into a stable atom.
Emitting an alpha particle, decreases the mass number by four and atomic number by two.
Emitting gamma ray reduces the excess energy of the radioactive atom.