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.
Are there choices? If there are choices what are they?
The Mississippi River has many small tributaries, but its primary tributaries are the Ohio River and the Missouri River. The Amazon River also has a large number of tributaries, including the Rio Negro, which is one of the largest rivers in the world in terms of volume. The Nile’s primary tributary is the Atbara River.
Answer:
the answer is water. hope that helped
