instruction:
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.
question:
Fact 1: howling is used to warn other wolves by wolves. 
Fact 2: And somewhere a beagle howls a most pitiful sound.
answer:
wolves use sound to warn other wolves.


question:
Fact 1: Electron transport is the final stage of aerobic respiration. 
Fact 2: Electron transport is like a waterfall.
answer:
Transport like a waterfall is the final stage of aerobic respiration.


question:
Fact 1: Some precipitation that falls on land may soak into the ground, becoming groundwater. 
Fact 2: Rain is also known as precipitation.
answer:

Rain that falls on land may soak into the ground and become groundwater.