what is necessary for a convection cell to be set up in a fluid?\no thermal gradient\no thermal gradient and…

Brief Explanations:

Convection cells in a fluid form due to a difference in temperature (thermal gradient) which causes changes in density. Warmer fluid is less dense and rises, while cooler, denser fluid sinks, creating a cycle. Both a thermal gradient and density - changes are required.

Answer:

thermal gradient and changes in density