I was ble to find the image from the exercise online.
The heat transfer depicted in the image is most likely:
Convection or convective heat transfer
The meaning of convection or convective heat transfer is when the heat transfers from one place to another because of the movement of fluids.
In the picture given, you can see how the heat moves from the ground to the clouds and then the opposite. You can realise that by looking at the arrows that first go up and then they go down.