Answer: 44% oxygen, 22% magnesium and 21% silicon.
Step-by-step explanation:
Mantle covers vast majority of the earth's volume. Movement or convection in this layer is responsible for the seismic activity.The structure and composition of the mantle is either the result of geophysical investigation or rocks derived from mantle.
The constituents of mantle are 44% oxygen, 22% magnesium and 21% silicon. There is some amount of iron, aluminium, potassium and sodium in mantle.