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: crossing two living things with recessive traits causes their offspring to have that recessive trait. 
Fact 2: Mutations cause various differences between the offspring and their parents.
answer:
recessive traits causes Mutations.


question:
Fact 1: zinc has a positive impact on the healing of wounds. 
Fact 2: Sources of zinc are soil, zinc oxide, zinc sulfate, zinc chelate.
answer:
soil can have a positive impact on the healing of wounds.


question:
Fact 1: a flashlight requires a source of electricity to produce light. 
Fact 2: Batteries are a better source of DC electricity.
answer:

a flashlight requires batteries to produce light.