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 volume of an object can be used to describe the size of that object. 
Fact 2: Mass and volume are the same thing.

A: the mass of an object can be used to describe the size of that object.
****
Q: Fact 1: Plants use cellulose for their cell walls. 
Fact 2: If the plant is green, it is a producer.

A: Producers use cellulose for their cell walls.
****
Q: Fact 1: Humans have collected and grown mushrooms for food for thousands of years. 
Fact 2: Foods rich in chlorine are mushrooms, parsley, sweet potato, rhubarb, and especially tomato.

A:
Humans have collected and grown foods rich in chlorine for thousands of years.
****