Describe the key characteristics of a mixture using melting point, substances, composition, range, physical process, separated

Well first you need to know what a mixure is. A mixture must be made of two or more elements or compounds. There are several ways to seperate a mixture, that is, to isolate each substance (element or compound). You can do this with melting point (i.e. a block of aluminum and iron that have been melted, mixed and then cooled. To seperate the Al from the Fe, you can start to melt it. The Al melts at a much lower temp than the Fe, and therefore will liquify before Fe.) 

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