Although objects can go through physical and changes, the amount of matter in those objects remains the same. this is known as the law of conservation of matter. matter can be broken into smaller pieces, dissolve in liquids, change physical states, and undergo other changes while still conserving its mass. which pairs of matter demonstrate the law of conservation?

 The blocks of the same structure bundled in a pile.

B.  A snowman.

 The melted remains of the same snowman.

C. A lump of clay.

The same lump broken into three pieces.

D. 1 cup of water and one gram of salt, separated.

 The same cup of water with one gram of salt mixed in.

E. One apple.

 The same apple cut into slices.

ANSWER:

The correct options are these:

B. A Snowman and the melted remain of the same snowman.

C. Lump of clay and the same clay broken into three pieces.

E. One apple and the same apple cut into slices.

For all the three answers listed above, the mass of the pairs will remain the same because nothing has been taken out of them and nothing is added to them, they were just changed from one form to another. The other options are wrong because, something got added to the original material. 

it is the most commonly accepted one