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: hearing is used for sensing sound by animals. 
Fact 2: All cats are animals.
hearing is used for sensing sound by cats.

Fact 1: if something is outside during the day then that something will receive sunlight. 
Fact 2: Sunlight is made of both UVA and UVB rays.
if something is outside during the day then it will receive UVA and UVB rays.

Fact 1: All life relies on a relatively narrow range of pH, or acidity. 
Fact 2: Life during most of the Precambrian was restricted to bacteria and algae.

bacteria relies on a relatively narrow range of pH.