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: Experiments are often done in a lab. 
Fact 2: Experiments are central to the sciences.
labs are where science is done.

Fact 1: sunlight and rain can cause a rainbow. 
Fact 2: Rain comes from clouds.
sunlight and clouds can cause a rainbow.

Fact 1: when an electrical circuit is working properly , electrical current runs through that circuit. 
Fact 2: Electric shock is passage of electric current through the body.

when an electrical circuit is working properly it can shock.