D. a new substance is formed. if it is chemical change then it is actually changing to something new. In this case a new substance is formed. It is a completely different substance from what you started out with.
The correct answer is - dunes.
The dunes, or sand dunes, are a relief forms that are formed by deposition of material. In the process of forming a dune, the responsibility goes to the eolian processes (wind processes). The wind has its own mechanical power to erode the rocks, but it also has the power to transport the material. The stronger the wind, the bigger the particles it can transport, and vice versa. When the wind is transporting a certain material, in the case of the dunes it will be sand particles, eventually it will start to lose on speed, and as it loses on speed, it loses on power, so the sand particles are starting to fall on the ground and deposit. s more and more sand particles are depositing, the dune starts to form, and it is growing bigger as more sand particles are falling on it.
An astronaut is able to float slightly on the moon due to the gravity, the gravity being 1.62 m/s² which would be lighter then the earth's which is 9.78 m/s².
In most cases, as altitude increases, the air in the troposphere cools. Vertical mixing occurs as a result of warm air rising. However, a layer of cool air may form beneath a layer of warm air on occasion. Temperature/thermal inversion refers to this deviation from normal temperature.
When an inversion occurs, polluted areas (such as London and Donora PA) experience unhealthy air and an increase in smog because pollutants are trapped at ground level rather than circulating away.
