Iliac crest pain is not that common in the general population, but it is frequent in older individuals, runners (and athletes in general), lower back pain sufferersâ¦ But that doesn`t mean âregularâ people like you and me can`t experience it from time to time!
The mantle is composed of iron-magnesium silicates, and the crust is composed of roughly 5 percent iron. All together, iron makes up an estimated 35 percent of the Earth's mass. Oxygen. Oxygen, the second most abundant element on Earth, is found mainly in the crust.
The mantle layer is the largest of the class. About half of our planetâs mass. Extract from http://www.educationalrap.com/song/layer... The Crust. Outermost layer, thickness varies from 5 km under the oceans to about 60 km under some mountain ranges. The composition of the crust varies from the continents to the ocean.