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: if an object is black then that object absorbs all visible light. 
Fact 2: Light grains are quartz, Black grains are coal.
Coal absorbs all visible light.

Fact 1: wind is used for producing electricity. 
Fact 2: Wind powered energy is provided by the wind, collected by using a wind turbine.
Wind turbines can produce electricity.

Fact 1: a stove is used for cooking by generating heat. 
Fact 2: Fire generates heat and light.

A stove uses fire for cooking.