. Recall that matter cannot move without energy. What is the energy source
that moves the red dye? What is the energy source that moves the blue dye?
The energy source that moves the red dye could be a physical force such as gravity, mechanical force from stirring, or a chemical reaction. The specific energy source would depend on the context.
Similarly, the energy source that moves the blue dye would also depend on the context. It could be a physical force, mechanical force, or a chemical reaction.