D. high and low levels of silica in the different type of lava.
Explanation:
The volcanoes have different types of explosions. Some tend to be highly explosive, some less explosive, some don't have explosions at all, while some have combinations of different eruptions. The reason for this diversity in the eruption types is mostly the composition of the magma, or rather how high is the silica content in it.
Basically, the higher the silica level in the magma the higher the explosiveness, and the lower the silica level the lower the chances of explosiveness. This is the case because the higher amount of silica makes the magma thicker, so the gasses are trapped and they explode, while when the lower silica content makes the magma less thick, so the gasses are not trapped and explosions are lacking.
Factors which caused an Increase in Air Pollution in China:
A.) Coal Combustion
B.) Slash and Burn
C.) Excessive disposal of Garbage into Open Area
Hope this helps!
<h2>
Answer: The greater the distance to a galaxy, the greater its redshift</h2>
When we talk about the <u>visible electromagnetic spectrum</u>, we know it starts in violet-blue and ends in red.
Now, in this context the astronomer Edwin Powell Hubble observed several celestial bodies, and when obtaining the spectra of distant galaxies he observed the spectral lines were displaced towards the <u>red</u><u> </u>(red shift), whereas the nearby stars showed a spectrum displaced to the <u>blue</u>.
From there, Hubble deduced that the farther the galaxy is, the more redshifted it is in its spectrum, and noted that all galaxies are <em>"moving away from each other with a speed that increases with distance"</em>, and enunciated the now called<u> Hubble–Lemaître Law</u>.
This means in the past the distance between two galaxies was smaller than at present, being this the proof that <u>the universe is expanding</u> (like a balloon expands when it is filled with air or another gas).
At this poitn it is important to stay clear that <u>the redshift is not produced by the relative movement of the galaxies with each other</u>. This effect is in fact, due to the <u>own expansion of the space</u> among the galaxies.
A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault. A rift valley is formed on a divergent plate boundary, a crustal extension or spreading apart of the surface, which is subsequently further deepened by the forces of erosion.
