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.

Fact 1: pasteurization reduces the amount of bacteria in milk. 
Fact 2: Milk is pasteurized, as are pickles.
a process that reduces the amount of bacteria pickles does the same in milk.

Fact 1: when a hemisphere is tilted away from the sun , that hemisphere receives less direct sunlight. 
Fact 2: The less direct the sunlight, the colder the weather.
When a hemisphere is tilted away from the sun, the weather is colder.

Fact 1: the number of rings in a tree trunk can be used to estimate the age of the tree. 
Fact 2: Tree age, scion, nutrition and other factors that affect the overall health of the tree could affect rootstock resistance or susceptibility to Phytophthora.

The number of rings along with scion, nutrition and other factors affect the overall health of a tree.