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: Constriction occurs when the muscular walls of blood vessels contract. 
Fact 2: Dehydration causes vessels to constrict and blood to thicken.

A: Constriction causes blood to thicken.
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Q: Fact 1: Some parasites kill their host, but most do not. 
Fact 2: Tapeworms are internal parasites of vertebrates.

A: most tapeworms do not kill their host.
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Q: Fact 1: condensation is when change from a gas into a liquid by reducing heat energy. 
Fact 2: Condensation is the reverse of vaporization , or change from liquid to gas.

A:
The opposite of vaporization creates condensation by reducing heat energy.
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