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: most canyons are formed by flowing rivers through erosion over long periods of time. 
Fact 2: Erosion was monitored by means of erosion pins.
Example Output: Canyon changes are tracked with pins.

Example Input: Fact 1: measuring the hardness of minerals requires scratching those materials. 
Fact 2: Most gem stones are hard minerals.
Example Output: You can measure the hardness of a gem stone by scratching it.

Example Input: Fact 1: Brain cells die quickly if their oxygen supply is cut off. 
Fact 2: Many people contend that orgasms are highly intensified when the body is cut off from oxygen.
Example Output:
people contend that orgasms are highly intensified with no oxygen but brain cells die.