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: 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: a speedometer is used for giving a driver feedback on the speed of their vehicle. 
Fact 2: Speed is the magnitude of velocity.
A speedometer is used for giving feedback on the velocity of a vehicle.

Fact 1: burning fossil fuels increases the carbon in the atmosphere. 
Fact 2: Like coal, petroleum is a fossil fuel.

burning coal increases the carbon in the atmosphere.