Is the something missing from the question
erosion and weathering.
erosion as in breaking it down, weathering is also a cause of erosion, but in the case of rain, it would carry away the remaining sediments.
Explanation:
Molecular formulas show correct and accurate number of each type of the atoms which are present in molecule.
On the other hand, structural formulas show arrangement of atoms and covalent bonds between them.
For example,
The molecular formula for carbon dioxide is 
The structural formula is O = C = O
Answer:
The answer is...
Explanation:
Constructive Interference