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: Many consumers feed at more than one trophic level. 
Fact 2: Nutrient levels are referred to as trophic status.
Many consumers feed at more than one nutrient level.

Fact 1: rocks interacting with wind over long periods of time causes weathering. 
Fact 2: Rocks weather at different rates.
wind affects rocks.

Fact 1: landfills have a negative impact on the environment. 
Fact 2: Landfills are the places that our garbage is taken to be buried.

Burying our garbage has a negative impact on the environment.