How do you think Oxygen can be in the crust when it is a gas at room temperature in the atmosphere?

Answer: Through diffusion

Explanation:

Oxygen can be defined as the most abundant element on earth. It is a gas at room temperature. It becomes the part of the earth crust by the process of diffusion.

Diffusion is a process of movement of molecules from a region of high concentration to the low concentration. The oxygen remains in high concentration in the atmosphere diffuses into earth crust at low concentration.