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.

Q: Fact 1: if an object is black then that object absorbs all visible light. 
Fact 2: Black objects absorb all different wavelengths of light.

A: If something is black then it absorbs all different wavelengths of light.
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Q: Fact 1: treating water is used to remove harmful substances before drinking. 
Fact 2: Chlorine is also used to treat water.

A: Chlorine is also used to remove harmful substances from water before drinking.
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Q: Fact 1: the number of rings in a tree trunk can be used to estimate the age of the tree. 
Fact 2: Age of Pine trees (AGE) in years.

A:
the number of rings in a tree trunk can be used to estimate how many years old it is.
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