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: sound can be used for communication by animals. 
Fact 2: Sound occurs when a body, such as a vocal chord, vibrates, or moves back and forth.
Example Output: Animals may use vocal chords to communicate.

Example Input: Fact 1: a calculator is used for adding. 
Fact 2: Calculator performs basic arithmetic, such as addition and subtraction.
Example Output: arithmetic includes uses for subtraction.

Example Input: Fact 1: Humans have collected and grown mushrooms for food for thousands of years. 
Fact 2: Yeast and mushrooms are types of fungus.
Example Output:
Humans have collected and grown fungus for food for thousands of years.