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: a prism is used for refracting light. 
Fact 2: Refraction is the bending of a ray of light.
A prism can be used to bend a ray of light.

Fact 1: if a planet becomes too hot then that planet cannot sustain life. 
Fact 2: If a planet is too close to a star, then it will be too hot for liquid water to exist.
If a planet is too close to a star, that planet cannot sustain life.

Fact 1: when a cooler object touches a warmer object , thermal conduction occurs. 
Fact 2: Heat sink materials are chosen for their high thermal conductivity.

Heat sinks are designed to be cooler than the objects they're in contact with.