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.

Ex Input:
Fact 1: using a gasoline engine requires burning gasoline. 
Fact 2: Oil and gasoline are fossil fuels.

Ex Output:
Many engines burn fossil fuels.


Ex Input:
Fact 1: tectonic plates being pushed together causes earthquakes. 
Fact 2: Earthquake tremors and volcanic activity are frequent.

Ex Output:
tectonic plates being pushed together causes tremors.


Ex Input:
Fact 1: Pneumonia may be caused by an infection or injury of the lungs. 
Fact 2: Opportunistic infections, such as Pneumocystis carinii pneumonia, begin to occur.

Ex Output:

Opportunistic infections may be a result of an infection or injury of the lungs.