After studying the diagram posted above and the angles of the diagram. The value of the angle that is represented by the letter A is 23.5°. The correct answer choice will be number 2.
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Answer:</h2>
Feldspar can be used to classify the rock based on <u>composition</u>.
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Explanation:</h2>
Felsic rocks are the type igneous rocks which contain feldspar and quartz; and they are typically light in color. A rock which is classified as felsic is contains a high content of felsic minerals such as quartz, orthoclase, muscovite, plagioclase, etc.
The common example of this type of rock is granite. Their chemical composition through the use of Total Alkali Silica determines the name of the felsic rocks. Felsic elements don't have enough magnesium, calcium and iron to form mafic rocks such as pyroxene or olivine.
After decades of theorizing and searching, scientists are reporting that they’ve finally found a massive reservoir of water in the Earth’s mantle — a reservoir so vast that could fill the Earth’s oceans three times over. This discovery suggests that Earth’s surface water actually came from within, as part of a “whole-Earth water cycle,” rather than the prevailing theory of icy comets striking Earth billions of years ago. As always, the more we understand about how the Earth formed, and how its multitude of interior layers continue to function, the more accurately we can predict the future. Weather, sea levels, climate change — these are all closely linked to the tectonic activity that endlessly churns away beneath our feet.
