when rock is weathered and transported downtream, this is best seen as an example of the conservation of

Matter.

Explanation:

Matter is anything that has mass and takes up space. The mass of an object measures the amount of matter or substance the object contains.

Generally, matter exists in three (3) distinct phases and these are;

I. Solid.

II. Liquid.

III. Gas.

The law of conservation of matter states that, matter can neither be created nor destroyed.

This ultimately implies that, for any chemical reaction, there must be the same number and type of atom present before and after the chemical change.

Weathering can be defined as the physical and chemical breakdown of rock into smaller pieces called sediment.

Hence, when a rock is weathered and transported downstream, this is best seen as an example of the conservation of matter because the amount of matter remains the same after the weathering process (change in form of matter).