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.

Q: Fact 1: when a cooler object touches a warmer object , thermal conduction occurs. 
Fact 2: Thermal conductivity varies with sediment type.

A: When a cooler object touches a warmer object, conductivity varies with sediment type.
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Q: Fact 1: microorganisms cause food to spoil. 
Fact 2: Food poisoning occurs when spoiled food is eaten.

A: Microorganisms cause food poisoning.
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Q: Fact 1: Insects generally have two pairs of wings for flight. 
Fact 2: During transonic flight, the air moving over a wing can travel from subsonic to supersonic and back.

A:
Insects generally have two pairs of wings for moving themselves through the air.
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