What causes convection currents inside earth

Differential heating and pressure.

Convection currents occur when lighter (or not as dense) warm materials rise over cooler, more dense, and heavier material sinks below it. These movements occur inside the mantle, or the third from inner-most layer of the Earth, and are often the cause of tectonic plate moment.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms