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 speedometer is used for giving a driver feedback on the speed of their vehicle. 
Fact 2: Cars are vehicles and trucks are vehicles.
[A]: A driver feeds feedback on the speed of their car with a speedometer.


[Q]: Fact 1: Humans have collected and grown mushrooms for food for thousands of years. 
Fact 2: Yeast and mushrooms are types of fungus.
[A]: Humans have collected and grown fungus for food for thousands of years.


[Q]: Fact 1: a switch is used to start the flow of current in an electrical circuit. 
Fact 2: If there is music playing, then the current output is stored in the wav file.
[A]:
A switch is used to start the flow of playing music.