Answer:
diffusion
Explanation:
The process that allows the drops to spread out in the fish tank is called diffusion.
Diffusion is defined the movement of a substance from a region of high concentration to that of low of concentration.
The drop will spread out in the fish tank by diffusion because it is more concentrated than the water surrounding it in the tank.
Perfumes are able to spread out in a room by this process. A rotten smell dissipates across the environment through this mechanism also.
