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.

Example Input: Fact 1: howling is used to warn other wolves by wolves. 
Fact 2: And somewhere a beagle howls a most pitiful sound.
Example Output: wolves use sound to warn other wolves.

Example Input: Fact 1: Viruses cannot reproduce by themselves. 
Fact 2: Passwords multiply and reproduce amongst themselves.
Example Output: Viruses cannot multiply by themselves.

Example Input: Fact 1: threatening behavior causes a fight-or-flight response in animals. 
Fact 2: Different behavior patterns are used by a threatened rabbit.
Example Output:
Different behavior patterns cause a fight-or-flight response in animals.