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.

[Q]: Fact 1: using a gasoline engine requires burning gasoline. 
Fact 2: Oil and gasoline are fossil fuels.
[A]: Many engines burn fossil fuels.


[Q]: 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.
[A]: When a hemisphere is tilted away from the sun, the weather is colder.


[Q]: Fact 1: Some viruses can cause cancer. 
Fact 2: Cancer is an uncontrolled growth and spread of abnormal cells.
[A]:
Some viruses can cause an uncontrolled growth and spread of abnormal cells.