When warm air rises and cool air sinks towards earth surface. what is this known as <u>convection currents.</u>
Explanation:
Convection currents not only occurs in the air but also in other fluids like water. In the air, they are responsible for the blowing of winds of the atmosphere . In the oceans, they are responsible for ocean currents. Convection currents also occur in the mantle and are responsible for tectonic plate movements.
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The structure is called Cell wall made from cellulose.