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: Viruses cannot reproduce by themselves. 
Fact 2: Viruses include the Tobacco Mosaic Virus.
The Tobacco Mosaic Virus cannot reproduce by itself.

Fact 1: the sun causes water to evaporate more quickly by adding heat. 
Fact 2: Similarly, stars are referred to as suns, but our star is the Sun.
our star causes water to evaporate more quickly by adding heat.

Fact 1: treating water is used to remove harmful substances before drinking. 
Fact 2: Chlorine is also used to treat water.

Chlorine is also used to remove harmful substances from water before drinking.