What is a reversible reaction? and what are two examples of a irreversible reaction?

In reversible reactions, the reactants and products are never fully consumed; they are each constantly reacting and being produced. An example of an irreversible reaction is combustion. Combustion involves burning an organic compound—such as a hydrocarbon—​and oxygen to produce carbon dioxide and water.

You didn't post a list of words.

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