In the Shepard Tone Illusion...

A) there is a continual rising of sound with no drops in octaves
B) there is actually a drop in an octave as other sounds keep rising
C) there is a continual decrease in octaves
D) all of the above occur at one time or another in this illusion

i think the answer is

mass

thermophiles, notice the prefix thermo.

1. the energy lost to disorder metabolism     -entropy

2. related to or possessing motion potential     -kinetic

3. all of the chemical reactions in an organism required for maintenance of the processes of life entropy     -metabolism

4. possible; ability to go into action or perform work kinetic     -potential

5. the study of energy and its transformations thermodynamics     -thermodynamics

not sure if this what   you'r looking for would be percent composition