Here's why:
* Oxygen makes up about 46.6% of the Earth's crust by weight. It's the most abundant element in the crust, primarily found in compounds like silica (silicon dioxide) and various oxides.
* Silicon is the second most abundant element, making up about 27.7% of the crust.
* Other non-metals like aluminum, iron, calcium, sodium, potassium, and magnesium are also found in significant amounts.
While oxygen is not found in its pure elemental form in the crust, it's a key component of numerous minerals and rocks that make up the Earth's surface.
