Europe and Asia are in the same landmass, like you can see in this picture.
Answer:
It allowed land-grant colleges to perform experiments in the fields of rural farms.
Explanation:
Threats include:water controlintroduced species<span>development</span>
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.
There are four settled societies that each developed agriculture independently along major rivers that are traditionally considered the early river valley civilizations. The are the Mesopotamian civilizations, the Nile River civilizations, the Indus River civilizations, and the Yellow and Yangtze River civilizations.