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.

Example Input: Fact 1: air pollution can cause the pH of soil to decrease. 
Fact 2: Acidity is measured with a pH meter or with pH paper strips.
Example Output: air pollution can cause the Acidity of soil to decrease.

Example Input: Fact 1: irradiating food can be used to kill existing microorganisms in the food. 
Fact 2: Irradiation causes chemical changes.
Example Output: chemical changes can be used to kill existing microorganisms in the food.

Example Input: Fact 1: Fertilization occurs when sperm swim to an egg inside an archegonium. 
Fact 2: When conception occurs in the female, a sperm fertilizes an egg.
Example Output:
When sperm enters an egg, conception occurs.