As the mass and volume increases, the densit will
increase, decrease, or remain the same

We can't tell from the information given.

Density is the RATIO of mass to volume.  So, if mass and volume both
increase but their ratio decreases, then the density decreases.

But if mass and volume both increase and their ratio also increases,
then the density increases.

Examples:

-- Start with a pile of some kind of substance.
    Mass = 150 grams
    Volume = 100 cm³

    Density = (mass) / (volume) = (150 gm)/(100cm³)  =  1.5 gm/cm³

-- Add 50 grams of mass.  Mass = 200 gm.
    Add 50 cm³ of volume.  Volume = 150cm³.

     Density = (mass) / (volume) = (200 gm)/(150 cm³)  =  1.33 gm/cm³.
                                                                                  Density decreased.

-- To the original pile, add 100 grams of mass.  Mass = 250 gm.
                               add 50 cm³ of volume.  Volume= 150 cm³.

     Density = (mass) / (volume) = (250 gm)/(150 cm³)  =  1.67 gm/cm³.
                                                                            Density increased.

-- To the original pile, add 60 grams of mass.  Mass = 210 gm.
                               add 40 cm³ of volume.  Volume = 140 cm³.

   Density = (mass) / (volume) = (210 gm)/(140 cm³)  =  1.5 gm/cm³.
                                                                         Density no change.
                                                                 Same as the original pile.