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: Many corals secrete an exoskeleton that builds up to become a coral reef. 
Fact 2: Coral is calcium carbonate with a trade of carotene.

A: calcium carbonate becomes a  reef.
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Q: Fact 1: Organisms that live in marine biomes must be adapted to the salt in the water. 
Fact 2: Estuaries display characteristics of both marine and freshwater biomes.

A: Organisms that live in estuaries must be adapted to the salt in the water.
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Q: Fact 1: creating paper requires cutting down trees. 
Fact 2: To cut down a tree is like destroying a life.

A:
creating paper may cause destroying life.
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