What the material of PIETA​

Marble

The sculpture, in Carrara marble, was made for the cardinal's funeral monument, but was moved to its current location, the first chapel on the north side of the entrance of the basilica, in the 18th century. It is the only piece Michelangelo ever signed.

Explanation:

the mass and the sacrifice are similar because jesus christ is the victim and priest in both. the mass is different from the sacrifice in that jesus died for the remission of sins and cannot be  sacrificed again during the mass.