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: bacteria in soil convert atmospheric nitrogen into a form usable by plants. 
Fact 2: Plants have to have nitrogen to grow.
answer:
bacteria helps plants grow.


question:
Fact 1: looking at bright objects has a negative impact on the eyes. 
Fact 2: Most of the bright objects are stars.
answer:
looking at stars negatively impacts the eyes.


question:
Fact 1: if a tree falls then sunlight becomes available to the surrounding plants. 
Fact 2: Like all plants, it needs sunlight and warmth to grow.
answer:

If a tree falls, then sunlight becomes available to allow growth.