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: Antigens are molecules that the immune system recognizes as foreign to the body. 
Fact 2: An antibody binds to an antigen .
Example Output: antibodies binds to molecules.

Example Input: Fact 1: Evolution occurs by a process called natural selection. 
Fact 2: Adaptation and natural selection are discussed.
Example Output: Evolution occurs by a process of adaptation.

Example Input: Fact 1: contact between rocks over long periods of time causes rocks to smooth. 
Fact 2: Primary rock types are Sandstone, and Shale.
Example Output:
contact between shale over long periods of time causes them to smooth.