TASK DEFINITION: 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.
PROBLEM: Fact 1: recycling has a positive impact on the environment. 
Fact 2: Steel is a recycled and recyclable product.

SOLUTION: certain Steel products have a positive impact on the environment.

PROBLEM: Fact 1: Viruses cause many human diseases. 
Fact 2: Some smallpox viruses are maintained in laboratories.

SOLUTION: smallpox causes human disease.

PROBLEM: Fact 1: being burried under soil and mud changes vegetation into peat through extreme heat and pressure in a swamp over a long period of time. 
Fact 2: Bogs are characterized by cushion-like vegetation and an accumulation of peat.

SOLUTION:
being buried under soil and mud changes bogs through extreme heat over a long period of time.