<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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The correct answer that would best complete the given statement above would be rhododendrons, evergreen forests and decidious trees. Therefore, the correct answer would be option D. ALL OF THE ABOVE. <span>A highlands climate supports rhododendrons, evergreen forests and deciduous trees. Hope this answer helps.</span>