TASK DEFINITION: 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.
PROBLEM: Fact 1: Mammals conserve body heat with their hair or fur. 
Fact 2: Mammals Hair or fur covers the bodies of most mammals.

SOLUTION: Mammals conserve body heat with their fuzzy, protective covering.

PROBLEM: Fact 1: a prism is used for refracting light. 
Fact 2: Refraction is the bending of a ray of light.

SOLUTION: A prism can be used to bend a ray of light.

PROBLEM: Fact 1: sand dunes are formed by the wind transporting and depositing sand. 
Fact 2: Coastal dunes are the product of wind-deposited sand anchored by sparse mats of vegetation.

SOLUTION:
Deposited sand anchored by sparse mats of vegetation form sand dunes.