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: All chemical reactions require activation energy to get started. 
Fact 2: Chemical changes are a result of chemical reactions.
Example Output: Activation energy must be used before a chemical change happens.

Example Input: Fact 1: wind is used for producing electricity. 
Fact 2: Differential heating of air produces wind.
Example Output: Differential heating of air can be harnessed for electricity production.

Example Input: Fact 1: Passive immunity lasts only as long as the antibodies survive in body fluids. 
Fact 2: Antibodies are also called gammaglobulins.
Example Output:
passive immunity lasts only as long as the gammaglobulins survive in body fluids.