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: conserving resources has a positive impact on the environment. 
Fact 2: Humans meet some needs and wants by using resources found in the natural environment.
Humans have a negative impact on the environment.

Fact 1: plasma is formed by electrons separating from atoms in stars. 
Fact 2: Plasma is more common in stars, because making plasma requires high temperatures.
Plasma is formed in high temperatures of the sun.

Fact 1: chemical weathering causes iron in rock to oxidize. 
Fact 2: Asteroids are typically made of rock or iron.

chemical weathering causes iron in asteroids to oxidize.