Like purple ribbons, blue ribbons represent many things, and among these are two types of cancer, colon cancer and colorectal cancer. Blue ribbons are also used, particularly in Canada, as a symbol for another issue that is related to cancer, anti-tobacco and anti-second-hand-smoke awareness. Light blue ribbons represent prostate cancer and, as an alternative to pink, childhood cancer. Gold is yet another alternative color for childhood cancer.
Oxygen is the most abundant element in rocks in Earth's crust, composing roughly 47 percent of the weight of all rock. The second most abundant element is silicon at 27 percent, followed by aluminum at 8 percent, iron at 5 percent, calcium at 4 percent, and sodium, potassium, and magnesium at about 2 percent each.eologists think the temperature of Earth's outer core is about 6,700 to 7,800 degrees F (3,700 to 4,300 degrees C), and the inner core may reach 12,600 degrees F (7,000 degrees C), hotter than the surface of the sun. Only the enormous pressures found at the super-hot inner core keep it solid.
On Earth, oxygen and silicon are the two most abundant elements, with silicon only found in the Earth's crust. The Earth's crust mostly consists of silicon, aluminum, iron, calcium, sodium, potassium and magnesium. All these elements are present in igneous rocks throughout the Earth.