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: Plants use cellulose for their cell walls. 
Fact 2: If the plant is green, it is a producer.
answer:
Producers use cellulose for their cell walls.


question:
Fact 1: an animal requires energy to move. 
Fact 2: All dogs are animals .
answer:
All dogs require energy to move.


question:
Fact 1: howling is used to warn other wolves by wolves. 
Fact 2: Soon a chorus of howling coyotes join in and the whole area reverberates with noise.
answer:

reverberating noise is used to warn other wolves by wolves.