If mass remains the same while the volume of a substance the density of the substance decreases, decrease increases, decrease increases, stay the same decreases, stay the same

2. increases, decrease

Explanation:

The density of any object is given by the formula:

So if you have constant mass, and an increase on volume, the prodcut of dividing the same amount of mass by more volume will be a direct decrease on the density of the object, the same if you keep the mass but reduce the volume, as you have the same mass in less volume, the result would be an increase in density.

less than one you can't create energy