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: Light enters the eye through an opening called the pupil. 
Fact 2: Just behind the pupil is a lens.
Example Output: light enters the eye through an opening just in front of the lens.

Example Input: Fact 1: completing a circuit causes electricity to flow through that circuit. 
Fact 2: Electricity can give the opener a shock.
Example Output: completing a circuit can give someone a shock.

Example Input: Fact 1: Rivers are usually larger than streams. 
Fact 2: Small streams join larger ones and are, themselves, joined by even smaller streams.
Example Output:
streams join rivers.