What quantity is shown by the slope the density of a fluid the volume of a fluid the mass of a fluid the weight of a fluid?

The slope of a mass versus volume graph for a fluid represents its density. Density is defined as mass per unit volume, so if you plot mass on the y-axis and volume on the x-axis, the slope of the resulting line indicates the fluid's density. Therefore, the correct answer is that the slope shows the density of a fluid.