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: a vehicle is used for transportation. 
Fact 2: All traffic vehicles are Air Planes.

A: a plane is used for transportation.
****
Q: Fact 1: howling is used to warn other wolves by wolves. 
Fact 2: And somewhere a beagle howls a most pitiful sound.

A: wolves use sound to warn other wolves.
****
Q: Fact 1: gills are used for breathing water by aquatic animals. 
Fact 2: Fish are animals that live in water and breathe using gills.

A:
Fish use their gills to breathe water.
****