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: using a gasoline engine requires burning gasoline. 
Fact 2: Oil and gasoline are fossil fuels.
Example Output: Many engines burn fossil fuels.

Example Input: Fact 1: camouflage is used for protection by prey against predators. 
Fact 2: Cryptic coloration is a type of camouflage.
Example Output: Cryptic coloration is used for protection by prey against predators.

Example Input: Fact 1: Immunodeficiency occurs when the immune system is not working properly. 
Fact 2: Treatments are available for many immunodeficiencies.
Example Output:
Treatments are available when the immune system is not working properly.