Substances that make up a mixture their own properties once they are combined to form a mixture. . i need to study for finals.

I believe the answer to this is;
Substances that make up a mixture RETAIN their own properties once  they are combined to form a mixture. 
    I believe the answer is RETAIN because the combination in question is a MIXTURE. A mixture is a combination of various substances. In the case of mixtures, all the substances retain their own properties. That is; they remain the way they are and do not change. An example of a mixture is air. And to prove that air is a mixture;
The components of air retain their individual properties.
The components of air cannot be represented by a chemical formula
When the components of air combine, they do not show any form of chemical change, like heat release, change in pressure
  Hope i helped, have a nice day.

Okay well gravitational energy is matter forced by gravity making energy though the kinetic energy then the electric energy produces electricity from the kinetic energy and the kinetic energy gets its energy from the gravitational energy. was that the answer you wanted or something else?  

In any atom of any element, you will find protons and neutrons in the nucleus of any atom