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.) 

Most likely a is the answer - because  you generate   38 atp's but also consume an atp.   each atp gives approx. less than 4 kcal so probably a is the closest answer.

Cause its being chemically applied?