The reason the Indo- European languages dominated the globe geographically today was that <span> 'B) European colonization around the world helped spread the languages.'</span>
The water distribution on earth shows that most water in the Earth's atmosphere and crust comes from the world ocean's saline seawater, while freshwater accounts for only 2.5% of the total. Because the oceans that cover roughly 71% of the area of the Earth reflect blue light, the Earth appears blue from space, and is often referred to as the blue planet and the Pale Blue Dot. An estimated 1.5 to 11 times the amount of water in the oceans may be found hundreds of miles deep within the Earth's interior, although not in liquid form.
<h2>Right answer: The density of Earth's layers</h2>
The Earth is basically made up of layers, with the Earth's crust being one of the last layers (the surface on which we stand). However, <u>this crust is not continuous, it is composed of pieces called</u><u> tectonic plates</u><u>, and the places where these plates joint together are called </u><u>faults.
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When theses tectonic plates move or when sudden displacements in faults or cracks in the interior of earth’s crust occur; seismic waves are originated.
The seismic waves are the propagation of disturbances generated by small movements in a medium, <u>they propagate towards the earth's surface</u> causing earthquakes or low intensity seismic movements.
Now, <u>the speed of the waves</u> depends of the properties of the medium; which are fundamentally:
(1) the elasticity and (2) <u>the density</u> of the materials by which it is propagated.
<h2>Therefore, according to the speed of the seismic wave, the density of the Earth layer can be found.
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