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: wind causes erosion. 
Fact 2: Erosion is the physical removal of rock particles.

SOLUTION: Wind causes the removal of rock particles.

PROBLEM: Fact 1: killing microorganisms in food can be used to extend the shelf life of that food. 
Fact 2: Irradiation kills microorganisms that spoil food.

SOLUTION: Irradiating food can extend shelf life by removing microorganisms.

PROBLEM: Fact 1: mechanical weathering is when rocks are broken down by mechanical means. 
Fact 2: Water is a mechanical weathering force.

SOLUTION:
Water can break down rocks.