Na presentation about measuring mass, one of your classmates states, "two objects of the same size will always have the same mass.” is this statement correct? why or why not?

The statement is not correct.

Reason:
If two objects have the same mass, their respective densities determine their volumes.
By definition,
density = mass/volume.
or volume = mass/density.

Therefore if two objects have the same mass, the mode dense object (with higher density) will occupy less volume than the other object.