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: Cells cannot survive without oxygen. 
Fact 2: Life is responsible for oxygen in the atmosphere.
cells cannot survive without the atmosphere.

Fact 1: boiling is when liquids are heated above their boiling point. 
Fact 2: If the pressure is reduced, the boiling point is lowered.
Less heating is required to make a liquid boil if the pressure is reduced.

Fact 1: Skin color is a polygenic trait. 
Fact 2: Chapter 5 discusses polygenic inheritance and intelligence.

intelligence is an inherited trait.

