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.

Input: Consider Input: Fact 1: electricity sometimes is used for heating buildings. 
Fact 2: Nuclear fission is the only method currently used by nuclear plants to generate electricity.

Output: Nuclear fission can be used to heat buildings.


Input: Consider Input: Fact 1: Air pollution harms the respiratory and circulatory systems. 
Fact 2: An example of an air pollution reaction is the production of photochemical smog.

Output: Smog harms the respiratory and circulatory systems.


Input: Consider Input: Fact 1: Lakes are generally bigger and deeper than ponds. 
Fact 2: Then there's the big lake, Lake Superior, with all it's bays and tributaries.


Output: areas with bays and tributaries are bigger and deeper than ponds.