the air being heated from a fireplace,air from a furnace,boiling water,the air being heated in a hot air balloon.
convections purpose it to "recycle" warm and cold air or materials
It's "convection" (not convections),but those are the words used to describe the three methods of heat transfer.
False.
Winds are examples of convections currents
The Earth's core.
They move the hot and colder parts around.
hot, less dense air rises
Warm air rises, and cool air sinks.
convections
the convection currents will stop
They occur in the upper mantle and the convections come from the inner core but travel to the upper mantle.
noting it works (in the science meaning; to cause a change) a lot.