What are the consequences of purposely having an excess of one of the reactants?

When one reactant is in excess, there will always be some left over. The other reactant becomes a limiting factor and controls how much of each product is produced. While using excess reactants can help to increase percentage yields, this is at the expense of atom economy.

Explanation:

organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.

the answer would be a