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.
The correct answer is D. How national borders in a region change over time.
Explanation:
The main purpose of maps is to show geographical features including natural physical features such as mountains or rivers, and political features that refer to the use of land by humans and the divisions created by them. Due to this, through maps, it is possible to visually show cities, states, regions countries, etc. In this context, a series of maps can be used to show the evolution or change of national borders because this is part of political features. Also, other aspects such as policies, beliefs, or economic events are not geographical and due to this cannot be depicted through maps.
the sun/radiation (sorta)/ fusion/(yea pretty much the sun)
Answer:
I think database...............B
