Can somebody help with this please ?

B. Molecules of different types of atoms that are not attracted to each other.

Explanation:

On a broad basis, matter can be subdivided into pure or distinct substances and impure substances (mixtures);

Pure substances are distinct substances having the following properties:

From this criteria, we see that the second choice is nullified. This is because pure substances have their molecules attracted to each other.

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