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: gravity causes objects that have mass to be pulled down on a planet. 
Fact 2: Weight is the measurment of the force of gravity on a mass.
answer:
Weight is measured when objects are pulled down by gravity.


question:
Fact 1: hydropower requires damming a river. 
Fact 2: Hydropower is a renewable resource.
answer:
Damming a river can provide a renewable resource.


question:
Fact 1: Evolution is a change in the characteristics of living things over time. 
Fact 2: Characteristics include traits like shape, color, size, and texture.
answer:

evolution is the change in traits of living things over time.