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: soil is formed by weathering. 
Fact 2: Soils are formed by breakdown of rock.

Answer: Weathering is the breakdown of rock.


Question: Fact 1: increasing heat causes thermal expansion. 
Fact 2: Motion helps to increase body heat.

Answer: motion causes thermal expansion.


Question: Fact 1: treating water is used to remove harmful substances before drinking. 
Fact 2: Ordinary tap water can be full of harmful substances like chlorine, pesticides and heavy metals.

Answer:
treating water is used to remove chlorine, pesticides, and heavy metals before drinking.