Answer:
Convection.
Step-by-step explanation:
Due to the heat of the lamp, the liquid increases its temperature. This increase produces an increase in the energy and volume of the globs. But it also causes a decrease in the density of the bubble. As a result, they break off and rise to the top. We can see that the globs rise owing to convection because there is a transfer of heat in the fluid caused by the movement of the fluid's molecules with more energy towards the surface, where the molecules have less energy and are colder.