Convection currents occur in the MANTLE. The mantle is the second layer of the earth after the crust. The mantle is approximately 2900 km thick. Convection currents are triggered or fueled by the heat from the Earth's core.
The part of the mantle closest to the core gets heated. It then becomes less dense than the layers above so it rises. When this rising plume interacts with the crust it cools and becomes more dense than the layers below and so it sinks and this circular motion continues to form convection currents.
Answer:
b. The terrain is mostly desert and mountains
Explanation:
Afghanistan is a country that has proved to be extremely difficult to invade, and that has been the case for thousands of years. There is one major reason for this, the geography of the country. The country is dominated by very high mountains that create rain shadow and and deserts. The mountains themselves are extremely difficult for passing through, and even if they are passed by an invading army, they will take their toll. Once the mountains are passed, an invading army would face desert, very dry climate, very few food sources and very little water, with temperatures varying from scorching hot in the summer, to freezing cold in the winter. So even if an army passes through both of these natural obstacles, when it comes to face the natives it will be too weak to invade.
Their homes will likely be crushed by another lahar.These dangers incorporate surges, lahars, avalanches, pyroclastic streams, magma streams, and tephra aftermath. These perils can devastate a region as well as impact water quality and other wellbeing dangers in spots that survive. Some of Mount Rainier's risks are not related with an ejection.
