The density of the ice cream plus buoyant will cause the carbonation in root bear will cause gravity to push down on the ice cream and buoyant pushes the ice cream upwards, the ice cream floats because the buoyant force is greater than the weight of the ice cream.
The root beer exerts a force on all sides of the ice cream. These forces are all equal and cancel each other out. Gravity pushes downward on the ice cream. The ice cream floats because the buoyant force is greater than the weight of the ice cream.
When a stem cell divides, each new cell can either stay a stem cell or become a specialized cell, such as a muscle cell, a red blood cell, or a brain cell.