instruction:
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.
question:
Fact 1: Communities consist of populations of different species. 
Fact 2: Each species of animal is unique.
answer:
Communities consist of populations of different animals.


question:
Fact 1: the emission of sulfur dioxide causes acid rain. 
Fact 2: Sulfur in the coal becomes sulfur dioxide when burned.
answer:
Burning coal causes acid rain.


question:
Fact 1: Chemical bonds form when substances react with one another. 
Fact 2: Chemical Bonding A chemical bond is the sharing or transfer of electrons.
answer:

The sharing of transfer of electrons happens when substances react with one another.