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: the Himalayas were formed by rock folding. 
Fact 2: Movements in the earth's crust have folded and cracked the older rocks.

A: the Himalayas were formed from older rock.
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Q: Fact 1: Mollusks are invertebrates such as the common snail. 
Fact 2: Invertebrates have no backbone.

A: mollusks have no backbone.
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Q: Fact 1: Fractures heal when osteoclasts form new bone. 
Fact 2: Bone cells called osteoblasts add calcium to bones, then osteoclasts pull the calcium out of bones.

A:
fractures need calcium to heal.
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