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: breaking apart rocks can cause debris. 
Fact 2: Sledge hammers can be used to break especially hard ledges of rock.

Answer: hammers can cause debris.


Question: Fact 1: living underground can be used for hiding from predators. 
Fact 2: Predator and prey play a deadly game of hide and seek.

Answer: Living underground can be used to avoid playing a deadly game of hide and seek.


Question: Fact 1: Hormones control many cell activities, so they are very important for homeostasis. 
Fact 2: Homeostasis is the chemical equilibrium of the body.

Answer:
Hormones are very important for the chemical equilibrium of the body.