Which materials are most likely to be part a streams dissolved load

Explanation:

They are mostly soluble earth materials.

Dissolved loads are products of chemicals weathering.

Examples are dissolved soil minerals, dissolved rock minerals etc.

The products of chemical weathering of rocks dominate the dissolved loads in a stream. Most of these materials are in solution and can travel very far away unless they become precipitated.

b.) plain  

hope this

because there are alot of mountains