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.
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Question: Fact 1: Fractures heal when osteoclasts form new bone. 
Fact 2: Osteoclasts are multinucleated cells.

Answer: fractures heal when multinucleated cells form new bone.


Question: Fact 1: sunlight and rain can cause a rainbow. 
Fact 2: Rain comes from clouds.

Answer: sunlight and clouds can cause a rainbow.


Question: Fact 1: an image in a mirror is formed by reflecting light. 
Fact 2: Water is essentially a perfect mirror, reflecting colors almost unchanged.

Answer:
an image in water is formed by reflecting light.