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: rain causes erosion. 
Fact 2: With the rain comes floods, and with the floods come erosion and landslides.

SOLUTION: rain can cause landslides.

PROBLEM: Fact 1: Migrants typically travel long distances. 
Fact 2: Barn swallows are Neotropical migrants.

SOLUTION: Barn swallows travel long distances.

PROBLEM: Fact 1: a compass is used to navigate oceans. 
Fact 2: Nautical charts are used by mariners and boaters to safely navigate on the ocean.

SOLUTION:
Mariners use the compass to travel the ocean.