the answer is agriculture
Igneous rock derives it's name from the Latin word ignis which means fire. It is formed when the magma after volcanic eruption gets cool and solidified either on the surface of earth crust or inside the earth crust. These rocks are characterized by their hardness. These rocks undergoes no chemical weathering but exhibit very low mechanical or physical weathering may occur. Therefore, hardness is the property which can be used to identify the origin of an igneous rock.
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.
Answer:
Humans alter their environment in many ways. We burn fossil fuels to produce electricity and to power cars, airplanes, and much more. We also remove land to build businesses, homes, and stores, and to grow food. We cut down forests to make things like paper, desks, and houses, and we hunt or raise animals for food. And lastly, we divert rivers to store water in reservoirs and to irrigate farmland.
