Answer:
Convection currents transfer heat from one place to another by mass motion of a fluid such as water, air or molten rock. The heat transfer function of convection currents is what drives the earth’s ocean currents, atmospheric weather and geology. Convection currents form because a heated fluid expands, becoming less dense. The less-dense heated fluid rises away from the heat source. As it rises, it pulls cooler fluid down to replace it. This fluid in turn is heated, rises and pulls down more cool fluid. In geology, molten rock in the mantle rises up from the bottom of the mantle after becoming hotter and less dense from the heat of the earth’s core. As the rock loses heat into the earth’s crust, it becomes relatively cooler and more dense, sinking back down to the core.
Therefore your answers are:
A, Less dense material rising, denser material sinking.
C, Some sort of liquid cycle: rising when hot, falling by gravity when cooler.
B, The cycle of Earths Materials in the mantle.
A pot of soup cooking could be modeled as an example of a convection current but is not the definition of it.
Dye in a bucket of water that goes up and down is not an example of a convection current.
