instruction:
Combine the given two facts to write a concluding fact. Note that there should be some parts of the first and second facts that are not mentioned in this conclusion fact. Your combined fact should be the result of a chain between the two facts. Chains form when two facts connect together to produce a concluding fact. An example of a chain is: "pesticides cause pollution" (fact1) + "pollution can harm animals" (fact2) → "pesticides can harm animals" (conclusion fact). Parts of the concluding fact overlap with the first and the second fact. To construct such a  concluding fact, a useful way is to borrow the subject from one fact and the ending conclusions from another fact.
question:
Fact 1: plasma is formed by electrons separating from atoms in stars. 
Fact 2: Most of the matter in stars is in a plasma state.
answer:
electrons separate in stars.


question:
Fact 1: a barometer is used to measure air pressure. 
Fact 2: Uses Elemental mercury is used in thermometers, barometers, and pressure-sensing devices.
answer:
Elemental mercury helps measure air pressure.


question:
Fact 1: keeping food cold is used for keeping food fresh. 
Fact 2: Fresh food is better tasting and better nutritionally, anyway.
answer:

Keeping food cold makes it better tasting and nutritionally better.