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: cutting down trees has a negative impact on an ecosystem. 
Fact 2: Ecosystems are living communities.
Example Output: Cutting down trees has a negative impact on living communities.

Example Input: Fact 1: gills are used for breathing water by aquatic animals. 
Fact 2: Fish are backboned aquatic animals.
Example Output: fish use gills for breathing water.

Example Input: Fact 1: freezing means changing from a liquid into a solid by reducing heat energy. 
Fact 2: Liquids freeze when they change to the solid state.
Example Output:
a liquid is frozen when it becomes a solid.