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: thick fur can be used for keeping warm. 
Fact 2: Carpet beetle larvae feed on the keratin and chitin commonly found in wool, fur, or feathers.

Output: keratin can be used for keeping warm.


Input: Consider Input: Fact 1: a plant requires water to grow. 
Fact 2: Clouds form by the condensation of water vapor.

Output: a plant requires Clouds to grow.


Input: Consider Input: Fact 1: a pulley is used for lifting objects. 
Fact 2: Tower cranes use pulleys to lift loads.


Output: a crane uses pulleys.