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: when an electrical circuit is working properly , electrical current runs through that circuit. 
Fact 2: Electrical circuits require a complete loop through which the electrical current can pass.
Example Output: Electricity completes a loop in a circuit to work properly.

Example Input: Fact 1: a laser is used for producing light. 
Fact 2: Light contains energy.
Example Output: A laser is used for producing energy.

Example Input: Fact 1: Differentiation is the process by which unspecialized cells become specialized. 
Fact 2: Cells are the basic unit of life .
Example Output:
Differentiation is the process by which unspecialized basic units of life become specialized.