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: Carbon may be stored in sedimentary rock for millions of years. 
Fact 2: Sedimentary Rocks One of the commonest sedimentary rocks is sandstone.

A: Carbon may be stored in sandstone for millions of years.
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Q: Fact 1: Earthworms are important deposit feeders that help form and enrich soil. 
Fact 2: For instance, in the forest, plants use sunlight and soil nutrients to grow.

A: earthworms help plants grow.
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Q: Fact 1: Aggression is behavior that is intended to cause harm or pain. 
Fact 2: If they are around aggressive dogs, they learn to be aggressive.

A:
dogs can learn behavior that is intended to cause harm or pain.
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