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: webbed feet are used for moving faster through water by aquatic animals. 
Fact 2: Ducks generally have webbing on their feet.

SOLUTION: Ducks can move fast through water.

PROBLEM: Fact 1: faulting of rock in Earth 's crust causes earthquakes. 
Fact 2: Fault zones are plates in the earth that slide and collide.

SOLUTION: plates in the earth collide which causes earthquakes.

PROBLEM: Fact 1: friction causes the speed of an object to decrease. 
Fact 2: After applying the brakes firmly and slowing to the desired speed get off the brakes.

SOLUTION:
brakes cause friction.